


Toxicant

by SeptSapphire



Series: Baby are you a doctor? (Because I've got an inter-dimensional parasite) [1]
Category: Stranger Things (TV 2016), Venom (Movie 2018)
Genre: Alternate Universe - Canon Divergence, Bisexual Steve Harrington, Crossover, Gay Billy Hargrove, M/M, Possession, Season 3, Stranger Things Spoilers, Swearing, it takes interdimensional interference for these idiots to realize they love each other, they'll get there eventually
Language: English
Status: Completed
Published: 2019-07-15
Updated: 2019-08-01
Packaged: 2020-06-28 15:30:33
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 14
Words: 34,312
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/19815184
Author URL: https://archiveofourown.org/users/SeptSapphire/pseuds/SeptSapphire
Summary: Season 3 spoilers!The mind flayer enters Billy Hargrove, but instead of breaking people down to make his own body, he decides Billy’s suits him just fine. Billy, surprising even himself, finds he doesn’t entirely hate that; there are certain benefits to sharing a body with some kind of trans-dimensional monster, and maybe,maybe,some of them wear stupid sailor outfits.The whole thing might not be so bad after all, except Billy’s mind flayer isn’t the only one.Billy-centric season 3 rewrite/crossover with Venom





	1. Infection

**Author's Note:**

> This fic was inspired by [fairlyoddchica's post on tumblr](https://fairlyoddchica.tumblr.com/post/186199953699/concept-the-mind-flayer-isnt-out-to-kill) about an au where the mind flayer is more like Venom, and I got a little carried away and turned a little drabble into a big multi-part full retelling. ...Oops.

Hands gripping tight to the steering wheel, Billy wondered once again why exactly he was doing this.

Sure, he’d put on the act for Mrs. Wheeler, laying on the charm, but it was supposed to _stay_ an act. Harmless flirting, nothing serious, just enough to put up a front without any commitment to following through. And yet, somehow he’d fucked it up, and before he knew what he was saying he’d agreed to meet her at some shitty motel for “swim lessons.” 

But even stupider than agreeing was getting in the damn car in the first place. He had no intention of fucking her – probably wouldn’t be able to anyway if he was honest, so he’d ended up driving in circles around Hawkins’ back roads, too worked up to turn around but too self-preserving to keep going. What the fuck was he supposed to say, exactly, if she was waiting there for him? ‘Sorry, Mrs. Wheeler, I know you brought the whole damn book club to the pool each day just to ogle me, but I’m-”

Something shot out from the side of the road, and Billy cursed bumfuck Indiana yet again for its goddamn wildlife even as he jerked the wheel. It wasn’t bright enough to see more than a dark black blob – real nice streetlights in this shithole town – hurtling toward his wheels, moving too fast for the Camaro to dodge. A deafening slam rocked the car, and Billy cursed again, wincing at the impact of flesh on metal and the horrible crunching noise of the side of his car. The car skidded under his hands for a few more feet, thrown halfway across the road by the force before coming to a shuddering stop. “Fuck,” Billy growled, knowing something that had sent him flying so far would probably have left a pretty damn noticeable dent in the car. Though, he had to admit, hitting some kind of deer or something at least gave him an excuse to bail on Mrs. Wheeler without looking suspicious.

Billy’s hand fumbled behind him to pop the lock on his door, and he slid himself out to check the damage. He came around the car, frowning at where the sleek blue had been marred by the impact and a set of scratch marks – probably from the thing’s antlers. He glanced over at the side of the road again, trying to make out what exactly he had hit, but-

It wasn’t there.

And that had to be wrong, because there was no way any deer would have just gotten up and fucked off on its own after a collision like that. In fact, now that he looked, there wasn’t even any blood on the pavement, though there was… oil? No, he thought as he got closer to it, not oil, some kind of thick black goo.

A rustling in the bushes made his head snap back up. Whatever the fuck was going on here, he really didn’t want to stick around and find out. He should just head back for the car. But the rustling grew louder, and the bushes at the side of the road began to shake, and before Billy could even turn away there was something leaping right for him.

It collided with his face, drowning out his vision and sending him a step backwards into the side of his car. He tried to grab at it in a panic, rip it off his face, but his hands only came away with what felt like more of that fucking goo. Billy felt the briefest sense of something inside him, inside his _head_ , before his muscles slackened involuntarily and his vision was swallowed in darkness.

~~

Billy’s vision came back blurred and too-bright, light pulsing against the back of his skull. Images swam in front of his eyes, too fast to hold onto. And there was… a presence, some sort of chill, and it felt… _inside his head._ And it was displeased with the washed-out film crawl.

 _Who are you?_ And Billy didn’t know who’d thought that, him or _it_ , and didn’t think he wanted to know.

Some images became clearer, focused longer. Brightly lit beaches in the California midday sun, shimmering with vibrancy. The waves were too blue, his mother’s sundress too white-

Abruptly the scene changed. A dinner table, just as bright yet this time the light leeched the color out of the room instead, bathing it in a sickly pale hue. Neil’s fingers, clenched into fists. A swell of pain on his lip, sudden, unbidden.

Another change, and this time he could practically feel the heat of the bonfire roaring in front of him, bathing his face in an orange glow. The beer between his fingers dripped cold condensation onto his thigh. Across from him, Tommy opened his mouth, but nothing came out.

What was happening to him?

_What do you want?_

He was behind the wheel of a car, his car, and wind spilled through the cracked window to card through his hair. A flash of red caught his eye, and he turned to the right, watching Max’s long hair whip wildly in the wind as she stared sullenly out the window. Almost not of his own accord, his hand rose, then rested on her bright hair, ruffling the strands until she pulled away and fixed him with a glare bordering on a begrudging smile.

The wind stilled and he adjusted, lounging at the back of a classroom, gaze tilted away from the teacher and fixed on the back of soft-looking curls of hair. His cheeks felt warm, but he kept staring at the back of Steve goddamn Harrington’s head until the world shifted around him again.

This time he was leaning against his car, staring up at the Byers’ shitty house. The door slammed open and Steve came strutting out, and this time he could hear himself speak, feel his own lips shape an obnoxious grin and goad, “Am I dreaming or is that you, Harrington?”

Steve’s flippant “Yeah it’s me, don’t cream your pants” was just as audible, and Billy chased that dark anger that bubbled up inside him till he found its root and-

Not that. He hadn’t wanted that. Well, he had, he’d thought he had, but he didn’t really. He’d wanted…

Abruptly, cold night air chilled the sweat on his skin, and the too-bright tint to his vision faded. He was still pressed against his car, but at some point he’d lowered himself to the ground, and he was back in the middle of the road instead of the Byers’ front lawn. He drew short, ragged breaths, and raised a hand up to his face, but didn’t feel even a trace of the black sludge.

Billy struggled to his feet, one hand braced against the car. His gaze flicked side to side, like a cornered animal trying to escape its predator, but whatever had attacked him wasn’t anywhere in sight. As his breath began to even out he scrambled back into the car, almost ripping the door off its hinges in his rush, and threw himself back down the road the way he came.

_“What the fuck?”_


	2. Manifestation

Billy halted himself a few steps away from the house, trying to get himself under control. He could hear the muffled sounds of the tv through the walls, so he figured Neil must still be up, and the last thing he wanted to do was draw attention to himself. Not that Neil would give a fuck that he was getting back so late, not as long as Max was where she was supposed to be, but if he came tearing into the house breathing heavy and shaking he was sure Neil would have something to say about it.

He waited until the hitch in his breath was almost gone before slipping the door open, eyes sliding towards the couch. Neil barely glanced over at him, obviously uninterested so long as he couldn’t find a reason to give Billy shit, and Billy quieted a relieved breath as he closed the door behind him and headed straight for his own room.

Out of sight, he let the tension slump out of his shoulders – well, most of it. He really shouldn’t still be this jumpy after the crash, even if some kind of rabid raccoon or something had flung itself at his face. He must have just hit his head from it, because that was the only thing that would explain those weird thoughts and the aching throb of a headache that wouldn’t leave him. Shit, he hoped the little fucker didn’t have rabies. He spun to face the mirror on his wall, thinking he should probably check for cuts just in case.

He didn’t see blood, but he raised a finger to trace a dark, branching line that ran down the side of his face, under his skin. What the fuck was that? Maybe… broken blood vessels? But just as quick as he’d noticed it, it seemed to be fading back into his skin, until it was practically unnoticeable. He was left blinking at his own face, wondering if there had ever been anything there at all or if he was still just so keyed up he’d imagined it.

Jesus, what a fucking pussy he was being. It wasn’t like this was the first accident he’d gotten into, or the first case of head trauma either. What was his problem? He’d just… he’d just sleep it off. He’d deal with it tomorrow, and when he headed back to the pool in the morning he was sure he’d be able to put tonight out of his mind completely. Resolved, he collapsed onto his mattress and, despite the buzzing beneath his skin, was out no later than his head hit the pillow.

~~

Billy woke with a start, groggy eyes slamming open and leaping to a seated position all at once. He blinked against the sleep in his eyes and the unusual darkness of his room. What time was it? He turned to the clock next to his bed and cursed when he saw it was only 5:30 am. He usually slept till at least 8, and by the time he got up Susan and Neil would have already left for the day so he could leave for the pool without seeing either of them. But they didn’t leave until 7, and he still felt like shit, to the point where he knew he’d slip up and any confrontation with Neil would probably give him a nice new set of bruises to take to work that morning. He tried to lay back down and go back to sleep, and maybe he could have, he was certainly tired enough, but he was fucking _sweating_. Which didn’t make any sense, because compared to California, Hawkins had always been a fucking ice box, and he’d already kicked the covers to the foot of the bed at some point last night. But the longer he tried to go back to sleep, the more insistent the need to cool off became.

He slammed himself out of bed, unable to ignore it any longer. He was still dressed from last night, clothes a little stiff from sweat, but that was just going to have to work for now because if he spent one more goddamn minute in this sauna of a house trying to get his sweat-slick clothes off he might actually combust. He shoved swim trunks and a towel in a bag, figuring if he showed up a little early for his shift at the pool no one could really blame him when it was so hot today, and dug around in his jeans until he fished out his keys. 

He swung his door open with more force than he’d intended, feeling it slam into the wall and reverberate, and if he’d had any concerns about drawing Neil’s attention so early in the morning they were pretty damn useless now. He stalked straight for the front door, hoping to avoid him entirely, but no such luck; Neil came striding out of the kitchen, a furious anger in his eyes. He opened his mouth, but at once a horrible, simmering anger reached its boiling point inside of Billy, and he clenched his fists to stop himself from driving them into his father’s face. Instead, he bypassed the man completely and kept heading towards the door.

“Hey!” Neil shouted after him, driven angrier by his surprise. Somewhere inside his mind, Billy recoiled at the tone. Years of Neil’s training screamed at him to stop, to turn back around, to take a beating now to avoid a worse one in the future. But right now he… he didn’t give a fuck. He wrenched the front door open, even as Neil growled, “where the fuck do you think you’re going?”

Billy flashed him one of his nastiest smiles and simply said, “out.” Neil’s furious look did nothing to stop him, and Billy only regretted that he couldn’t see his expression when Billy slammed the door shut in his face.

It wasn’t until he’d peeled out of the driveway that a wash of cold fear came over him again. What the fuck did he think he was doing? He could have just slipped out the window for god’s sake, not antagonized Neil and practically guaranteed himself getting the shit kicked out of him when he next showed his face. 

_Fuck. Real great job there, Hargrove._ Not like he could turn around now though, especially with that too-tight restlessness still prickling under his skin. He’d be early since he usually took second shift, but maybe he’d head to the pool anyway and see if he could convince Heather to give him her opening shift instead, if only to give himself something physical to do and burn off this excess energy with.

~~

Luckily for him, when he arrived at the pool Adam was actually relieved to see him rather than annoyed. “Billy!” he called, “you see Heather anywhere? She was supposed to open today but I think she bailed on me.”

Billy shook his head, not too concerned. It really wasn’t the first time Heather had been a no-show for her early shift. “Give her an hour, I’m sure she’ll turn up. Probably overslept – not sure how she could when it’s so damn hot today, but whatever.” Adam gave him a weird look, like he wasn’t making any sense, but apparently didn’t find it weird enough to say anything. 

“Tell ya what,” Billy said, “I’ll take Heather’s shift instead, she can take mine when she gets here. As long as I can hop in the pool before any of the little fuckers get here and piss in it.” 

Considering they had an hour or so before people really started showing up, and it would only take a bare few minutes to wrestle the old gate open, it was an easy enough deal for Adam to agree to. Which was great, because standing out in the sun, even this early, was really making him sweat again.

~~

By the time midday rolled around, Heather was still AWOL, and Billy was getting real sick of sitting in the lifeguard chair. He’d swam a few laps this morning which had finally kept him cool enough to think straight, but that had been hours ago, and the sun had long since heated him back up. Plus he was starting to get annoyed with trying to avoid Mrs. Wheeler’s gaze, since she wouldn’t fucking stop staring at him.

**_"Hot."_ **

Billy damn near leaped out of his chair; as it was, he managed to grab onto the armrests just quick enough to keep himself upright, but only barely. Who the fuck said that? He glanced around himself, even risking locking eyes with Mrs. Wheeler in his search, but didn’t see anyone else batting an eye.

Lauren’s shout of “Yo, Billy!” nearly gave him a fucking heart attack. Grip on the armrests a little tighter than usual, he poked his head over the side of the chair, where Lauren looked up at him, arms crossed. “Some kid ate too much ice cream and got sick over by the gate, can you go to the supply shed and get the bleach? I’ll take over for you here.”

 _Of course, wouldn’t want you getting your fucking hands dirty, would we_ Billy thought unkindly, but wasn’t stupid enough to say out loud. Don’t get him wrong, he’d have loved to rile her up, but she and Adam were fucking and he’d rather keep his job. Plus it gave him an excuse to get out of the damn sun for a few minutes. He obligingly swung himself down from the chair, settling on an only slightly-venomous “chair’s all yours, sweetheart” as she tossed him the keys to the supply shed.

Inside the shed was dark and cool, and Billy took a minute just to rest himself against the old metal shelves and breathe in the quiet. Who knew Hawkins could get so damn hot? After the feeling of near-heat stroke passed, he begrudgingly pushed himself off the shelves and turned to face them, looking for the bleach. It was tucked into a corner on the lowest shelf, so he crouched low, fishing out his prize.

Bleach in hand, he was suddenly really, really hungry. Like, overpoweringly hungry. Or thirsty? Whichever it was, he found himself eyeing the bottle, fingers coming up to settle on the cap, almost like-

**_"No."_ **

That voice again, and he stilled abruptly, blinking down at his hand over the cap. But he didn’t drop it, he still felt…

“Billy? Are you in here?”

Billy straightened on reflex, forgetting about his position and slamming his head into the shelf above him with a pained groan. Instantly he dropped the bleach bottle, two panicked parts of his brain trying to decide between the most pressing concern right now, Clorox or Mrs. Wheeler.

Apparently Mrs. Wheeler won out, because he stood to face her, pressing a hand to the tender spot on his head. She hardly seemed to notice the gesture, instead prattling on about how she hadn’t meant to not come last night, really, she just saw her husband doing… something… really, it was hard to pay attention to whatever she was talking about.

What the fuck had just happened? Sure, pissing off Neil might have been suicidal, but it had been a whole world of difference from a sudden desire to drink _cleaning products_. And since when was he hearing voices? It was all too much to think about, too much to deal with, with some overbearing pool mom trying to apologize for not showing up to a meeting he hadn’t gone to himself and didn’t even want to go to in the first place.

With an annoyed grunt, he cut her off, shoving past her in the enclosed space of the shed, biting out a curt “Leave me the fuck alone.” He needed some air.

~~

“Guys, I’m not kidding. There’s something weird going on, and I’m worried.”

Next to Max, Mike gave an unattractive snort. “About Billy? What’s there to be worried about, other than that he’s being an even bigger douchebag than usual?”

Max frowned back at him, getting frustrated. Normally she’d be the first one to say Billy was a douche, but she got to do that, she was his sister. When Mike said it? It just made her want to hit him. 

“No offense, Max, but Mike has a point.” That was Lucas this time, probably trying to head her off before she really did end up punching Mike. “I’m not sure Billy getting pissed at his dad and storming out is really our kind of problem.”

Max clenched her jaw against the words that threatened to spill forward about just why Billy giving Neil anything other than a ‘yes, sir’ set off red flags. Like hell was she telling anyone else about that, least of all people who didn’t even _like_ Billy. With good reason, admittedly. But he’d been a lot less of an asshole recently, to her and her friends, and this morning… something about it just wasn’t right.

“Look,” she tried, “I get what you mean. But you don’t know Billy like I do. And Will said…” she trailed off for a beat, looking over at Will, whose eyes were a little more shadowed than they had been yesterday. “Will said all that stuff about the Mind Flayer, and I just-”

“I think we should try it.” Another hand suddenly grabbed hers, and Max looked over to see it was El, who’d just spoken. She looked calm, near-certain that she could get the boys to do it if she showed her own support, and she was probably right. Max had never felt more relieved to have the other girl on her side.

Almost instantly the boys looked like they were changing their tune. “It wouldn’t hurt to check I guess,” Lucas mumbled, “provided Billy doesn’t kill us afterwards. Whether we’re right or not.”

Mike looked like he was on the verge of arguing, but was too preoccupied with getting back on El’s good side to really commit. “Fine,” he finally bit out, with a little twist of his lips that indicated the word was especially distasteful. “But how are we gonna know?”

Will shifted, bringing up a hand to rest on the back of his neck. “I think I have an idea. The Mind Flayer, he…” he paused, and Max could practically feel herself leaning forward in anticipation. “He likes it cold.”

**Notes for the Chapter:**

> I don’t remember them giving the other pool employee/manager names but it’d be pretty goddamn weird for Billy to refer to his coworkers by anything but their name so, pool cast, I have dubbed thee ‘Adam’ and ‘Lauren’ until so proven otherwise.


	3. Fever

By the end of his shift, Billy felt like he was going crazy. It was only 2 pm, but it felt like he’d been up in that stupid chair all day, trying to ignore whatever the hell had come over him in the supply shed until he was somewhere other than his job. Heather never showed up, but Lauren had taken one look at his sweat slick, too-pale face and decided it would be better to take over for him than have him work a double shift and be out two workers tomorrow. Not the most altruistic of intentions, but he’d take any excuse to get the fuck out of here.

Not that he knew where the hell he was going after this, he thought as he headed towards the changing rooms. He could go back to the house, Neil would be long gone, but if Max wasn’t out with the other geeks – or worse, they were all at the house – she’d probably realize something was up with him, and that was the last thing he wanted.

His thoughts were abruptly cut off when he noticed a piece of paper taped onto the changing room doors, with “Out of Order” hastily scrawled on it in some truly godawful handwriting. That was weird, Adam hadn’t said anything about closing them.

Whatever, his clothes were in there anyway. He was sure whatever was wrong with them couldn’t be so bad that he wouldn’t be able to _change,_ though that brought up questions of how a changing room could be out of order. Well, he’d glance around when he got in there – at least he’d know why they were closed if some old dude got grumpy about not having sauna access.

**_”Don’t open that door.”_** Fuck, who the fuck _was_ that? Again he looked all around him, but again there was no one there. He rested a testing hand on the door handle, pausing, and though he felt a sense of annoyance, the voice didn’t protest again, almost like it had resigned itself to being ignored.

He shouldered the door open, heading over to the locker he’d shoved his clothes in this morning, but before he could do much more than swing the door open he heard a noise, like someone else was in here. Wouldn’t have been too weird normally, but hadn’t the door said out of order? Not that he saw anything broken, but still, probably better not to let someone run around in here, especially if Adam saw them leaving later.

Things got a whole hell of a lot weirder when the scuffling noises turned into a taunting, “Billy,” which echoed off the lockers. Billy blinked, trying unsuccessfully to fend off a shockingly strong wave of anger that what sounded like a kid was not only where they shouldn’t be, but also _mocking_ him. He stalked down the row of lockers, narrowing in on the voice, and getting closer to the sauna, where he saw someone with their back turned.

He was having way too shitty of a day for this. He stormed inside, laying a heavy hand on the kid’s shoulder and grounding out a, “you’re not supposed to be in here,” turning them around only to blink confusedly at a mannequin. “The fuck-” The slam of the sauna door cut him off, and he whirled, pressing himself up against the glass window.

“Hey, let me the fuck out of here!” he snarled, slamming a shoulder into the door, and he was pretty damn sure the sauna didn’t have a lock on it but it refused to budge. He squinted against the glass, growling, “You’re so fucking dead,” trying to get a good look at who was doing this so he could beat the shit out of them later.

A bunch of little kids, looked back at him, and he thought maybe he recognized some of them but it was hard to tell through the smudgy window, but wait, wasn’t that- “Max? What the fuck is going on?”

Max just stared back at him and mumbled something that sounded like “please don’t be Billy,” but that didn’t make any _sense,_ what the hell was that supposed to mean…

Billy was gradually becoming aware that he was getting _really_ hot. He’d thought he’d been hot before, out under the sun, but this was _brutal,_ a horrible moist heat that felt like his skin was on fire and made his head pound. He clutched at the back of his skull, feeling the worst of it there, and something strange, something that reminded him of last night and waking up on the side of the road slumped next to his car. Was his sister’s little geek squad trying to burn him alive?

He was desperate for escape. Loosing a guttural scream, he slammed his shoulder into the door again, feeling it shudder underneath the force. He rammed the door again and again, feeling like he was about to be sick, or shake out of his skin, or have something finally tear loose.

With one last slam and the sickening creak of metal, the door finally gave way, and blissfully cool air replaced the stifling heat, fading the panic buzzing in the back of his mind. The kids had huddled together on the far wall, staring up at him with mouths agape, with some unfamiliar brunette standing like a trembling wall in front of them. Behind her, Max look more terrified than he’d ever seen her before.

**_”We should kill them.”_ **

“No!” He took a stumbling step backward, shaking his head. He wasn’t going to _kill_ the little idiots! They hadn’t stopped staring at him, in fact they may have even been staring harder at his little outburst, so he took another step back, one of his hands raising to tangle in his hair. Whatever had said that was _not happy,_ and felt tense and coiled to strike, but Billy was in control, and he wasn’t a fucking pushover.

One of the kids approached him – that brunette girl – and stared at him like she could see right through him. She didn’t say anything, just kept staring until Billy had to look away, instead meeting Max’s eyes, which were still blown wide in fear and uncertainty. “Max?”

Max swallowed thickly, but to her credit he could barely hear a tremble in her voice when she said, “yeah?”

“I think something’s wrong with me.”

~~

Billy’s still wasn’t entirely sure what was happening to him, but he figured at this point he should take whatever help he could get. Even if it came from Max’s little geek troupe.

He ran a hand through his hair for what had to be the hundredth time. “So let me get this straight,” he sighed, “you’ve seen this kind of thing before?”

The dark haired boy who looked like he’d blow over in a stiff wind – Mike? – huffed an impatient sigh. “ _Yes,_ that’s what we’ve been trying to tell you.” Billy very firmly restrained himself from punching the kid.

“And that’s why you knew it didn’t like the heat…?”

Their eyes subconsciously flicked towards one of their group, a boy with an awful bowl cut who hadn’t said much. “Will was, uh-”

“It was inside me. Last year. …The Mind Flayer,” Will said, haunted eyes meeting his own until Billy had to look away.

This was too damn weird to be true. And yet, he didn’t really have any other explanation. And while that night last October was still a little fuzzy around the edges thanks to Max _drugging him,_ he still remembered what had come out of that fridge. He’d thought maybe he was remembering it wrong, maybe he hadn’t really gotten a good look at it, but with everything happening now… “So what, I’ve got some kind of interdimensional parasite?”

**_”I am NOT a parasite!”_ **

“Alright, alright, Jesus, you’re not a parasite,” Billy grumbled under his breath, feeling the thing’s anger surge and then recede once again, placated. Only to find all the kids’ eyes staring at him like he’d gone insane. “ _What?_ ”

It was Lucas who broke the silence this time, asking, “Did you just speak to it?” Billy scowled, annoyed. It was talking to him! What was he supposed to do?

He looked a Will with an impatiently raised eyebrow, waiting for the kid to explain, since he clearly seemed to have a better handle on what had happened to him than Billy had. Instead, he only got a quiet, confused, “It never spoke to me…”

Oh. Well that was weird, because to Billy it felt like the damn thing never _stopped_ talking. “Yeah well maybe I just command a little more respect than you, kid.” He tried for a cocky grin, feeling it come out a little strained on his face.

Mike eyed him. “Maybe we should do the sauna thing again, try to get it out-”

“No! Fuck no!” Billy was _not_ doing that shit again if he could help it, that had _hurt_.

Max seemed to notice they weren’t really getting anywhere, or at least she was the first one to point it out. “Alright, something’s different this time, and I don’t think we’re going to figure out why sitting on our asses in the pool locker room.” She turned to her group of friends, dropping her voice a little, but the room echoed and there wasn’t much she could reasonably do to prevent Billy from overhearing. “I think we need help. Maybe we should tell Hopper, or Mrs. Byers-”

“No,” the brunette girl protested, and her name was something like Eve or Elle, “If we tell him, he’ll just want us to ‘stay safe’ and won’t let us help. And _he_ won’t be safe, and I won’t be there.”

Will seemed to agree with her, adding, “And I don’t want to tell my mom, not yet. I don’t want to worry her any more than she’s already been.”

The others grumbled a little, but reluctantly conceded the point. “Fine,” Mike agreed, “but if we can’t tell them, then who else are we supposed to-”

The whole damn group’s eyes lit up at once, and Billy might have been in the middle of some weird shit today but that was just downright freaky. Max turned to face him again, resting her hands on her hips and pulling her chin up. “Billy, we’re going to need a ride to the mall.”

“ _All_ of you? _Now?_ ”

**Notes for the Chapter:**

> Nobody:  
> Billy: I’m about to mentally roast these 12 year olds
> 
> Can you believe this is a Harringrove fic where Steve doesn’t even show up for three whole chapters because I sure can’t.


	4. Replication

As it turned out, yes, the kids _had_ meant _all_ of them needed to go to the mall. Billy included. Trying to fit six people into the Camaro had been an exercise in futility that ultimately ended with a real lack of seatbelts and Billy throwing his hands up and declaring that if any of them died on the way over he wasn’t taking responsibility. Not that he planned on getting in yet another crash with the Camaro, not while the side was still dented in from the last one. He made an annoyed grimace at the thing in his head for that, even if it couldn’t see it.

On top of that, they refused to tell him why they were even going to the mall. Max, who’d pulled the sister card to claim shotgun, just glanced out the window when he asked, muttering something about finding out soon. So clearly he wasn’t going to be a huge fan of the answer.

All this culminated in Billy Hargrove following behind a group of overexcited pre-teens in the new Starcourt mall, with an inter-dimensional monster in his head who was currently learning the wonders of capitalism, trying to walk far enough behind the group that he looked unassociated and close enough that when he talked to the voice in his head he didn’t look crazy. Well. He _was_ talking to a voice in his head, so maybe he couldn’t be so positive about that last one.

By the time they reached _Scoops Ahoy,_ some cheesy sailor-themed ice cream store, he wasn’t exactly thrilled. “You made me bring you all the way to the mall for _ice cream?_ ” he grated, pointedly ignoring the Mind-whatever’s interest at hearing the word ‘ice.’

 _On second thought,_ he reflected after the waft of amazingly cold air hit him, _I take it all back, I’m in fucking heaven._ His passenger made a similarly pleased noise. He hadn’t felt this cool all _day,_ and he really needed it after that sauna shit. Hell, he’d actually consider buying ice cream for the little shits if it meant they got to stay in here a little longer.

Unfortunately, it was in this same moment of glory that Billy made the mistake of actually looking in the store, only to stop dead in his tracks. Leaned up against the counter in what had to be a purposely-skimpy, completely ridiculous sailor outfit, was Steve fucking Harrington. Who seemed to be in a state of shock himself, taking in Billy traipsing behind the group of kids he’d initially smiled at.

**_“Who is he? Your pulse has quickened.”_ **

The sudden intrusion startled Billy back into movement, even as he muttered under his breath, “That’s none of your goddamn business.” 

**_“Everything of yours is my business,”_** it replied, sounding smug.

He figured this explained all the secrecy on the way here. It wasn’t like he hated Harrington, pretty damn far from it, not that he would ever tell someone that, and he didn’t really hold last year’s grudge anymore. But their last notable interaction had been the time Billy almost beat him to death, so saying things were awkward between them was a pretty severe understatement. Max’s insistence that he leave her friends alone, including Steve, made for a pretty good excuse for them to avoid each other whenever it wasn’t absolutely necessary. …Like now, apparently.

And truth be told, there was still something about his tendency to maybe get a little too invested before getting hit with an ice cold bucket of ‘he’s straight you idiot he’d beat the shit out of you if he knew not to mention if Neil found out and oh yeah, you almost killed him once so even if he was down it wouldn’t be with _you_ ’ that culminated in slightly nastier tendencies than his usual. He’d always been shit at look but don’t touch.

_**”I remember him now. He was in your head last night.”** _

Pointedly ignoring all the ways _that_ comment could be taken, Billy fixed Steve with a sharp-edged grin, overcompensating a little for being thrown off balance. “Harrington, nice outfit,” he said, riding the fine line between indicating the ridiculous shorts with his eyes and staring at Steve’s ass.

Steve’s flat stare was unimpressed. “Do you want ice cream or did you just come in to ogle the goods?” 

Billy’s eyes went a little wide, wondering if he’d been caught, but Steve didn’t look like he’d picked up on anything genuine, so he deflected with a “little bit of both, pretty boy,” because he’d never really been great with playing with fire either. Also, he couldn’t resist the little flush on Steve’s face when he didn’t back down from the taunt.

“Actually,” Max cut in, apparently taking her cue to interrupt the two of them, “we’re not here for ice cream.” She expertly ignored Billy’s inner voice proclaiming _**”I am,”**_ likely because she was lucky enough not to be subjected to it. “There’s something we’ve got to talk about.” She glanced around _Scoops Ahoy,_ which was flat empty aside from them, but still lowered her voice to add, “Alone.”

Steve raised an eyebrow at Billy, then looked back at her. Something between mild offense and complete confusion prompted Billy to blurt “Wait, _Harrington_ knows about this too?” because yeah, he figured that would finally explain why Steve’s primary friends were pre-teens, but Jesus, was he the _only_ one in this town who hadn’t known anything? 

To his credit, Harrington just shrugged, pretty damn nonplussed about his knowledge of weird government experiments and upside down dimensions. “I could say the same thing about you, Hargrove. But if you say so… follow me then.”

“Fine, but I still want that ice cream.”

~~

Steve led them all behind the counter and into the breakroom, where there was already a girl Billy was pretty sure he recognized from school, sitting across from a curly haired kid he also vaguely recognized. They both looked up at their entrance, and the girl half-sighed when she saw the kids and asked, “there’s _more_ of them?” When Billy slunk in behind them, newly-acquired ice cream in hand, she tacked on, “oh, so you do know people your own age!”

Steve rolled his eyes good-naturedly with a goofy little uptick of his mouth, and Billy rapidly decided he didn’t really like this girl at all. He stamped down the idiotic flush of jealousy. “Hey Robin, can you give us a few minutes?”

Robin looked unimpressed, but still obligingly got up, probably deciding she’d rather not be in a room where the number of people under fifteen outweighed the number of adults. “Gee, you crack a Russian code for a guy and this is what you get huh,” she groused, but grabbed a discarded sailor’s hat from the table before she walked back to the store counter.

“Russian code?” Mike asked, looking expectantly at the curly haired kid for answers.

“Not important right now,” Steve said, ignoring the offended little noise the curly haired kid made. “Dustin, scoot over,” he added, dragging the chair Robin had vacated out from under the table and flopping down unceremoniously. Billy leaned back against the wall and definitely did _not_ look at the way his shorts rode up at the movement. “So, what’s so important it couldn’t wait until after my shift?”

Mike, apparently having put the Russian code out of his mind for now, began, “So you remember the Mind Flayer? The thing that was in Will last year? It’s back… kind of.”

“Kind of,” Steve repeated dumbly, then, “what the fuck does ‘kind of’ mean?” Billy didn’t think he was imagining the way Steve’s hands tensed where they rested on his thighs.

“Well, it’s not acting the same,” Lucas continued. “Last year it was all murder-y, but this time it’s… not? Maybe? Just kinda chatty. Oh, and it’s not in Will this time either.”

“Then who-” Steve’s gaze slid over them, resting on Billy. “Oh. _Oh._ ”

Dustin’s reaction was much less contained. “The Mind Flayer is in _Billy Hargrove?_ He practically killed Steve on his own! We’re all doomed!”

“I’m right here, asshat,” Billy ground out. He ignored the mild bickering that ensued in favor of taking a bite of ice cream, and damn, this shit was amazing. He hadn’t hated ice cream before or anything, but he felt like he was seeing it in an all new light – one that made him polish off a lot more of it a lot faster than usual.

In the middle of another bite of ice cream, he became aware that the flurry of chatter had stopped completely, and everyone’s eyes were on him again. “What?” he mumbled from behind the plastic spoon.

Steve blinked like he was snapped out of a trance. “You… really like ice cream huh?” 

**_”It’s cold. I like the cold,”_** the voice grumbled, sounding pleased.

Billy shrugged. _Fair enough._ “It’s cold, he likes it,” he repeated obligingly, then returned to ignoring them and eating another bite.

“Yeah,” Steve muttered, “that’s _definitely_ not how that went down last year. Unless we could have used ice cream to ward off the demodogs the whole time.”

**_”Not likely. I am much more easily placated than he would have been.”_ **

Billy frowned. “He? As in, not you?” he repeated, and Steve started to ask who he was talking to but was shushed by El. 

**_”There are more of us. I was not in Will Byers – I only came through the gate this time._ He _was the one who came last time.”_**

“Well that would explain a lot,” Billy sighed, not sure if he should feel concerned that there was apparently a much nastier version of this Mind Jacker thing out there or just relieved it wasn’t in him. “He said he’s not the one who was in Will last year. That there’s another one, and he only came through the gate, like, yesterday.”

“The gate’s open?” Mike and El yelped simultaneously, at the same time Will said, “Then the one that was in me... He's out there somewhere.”

A loud shout of “Steve!” from the front of the shop interrupted them once more, and Steve winced like he was bracing himself for a particularly unkind fate. “Sounds like Robin’s on her last straw when it comes to free samples – I’ll be right back. Don’t go anywhere, and Hargrove, don’t let the Mind Flayer start eating the kids until I get back, yeah?”

Billy waved a hand in a mini salute. “Aye-aye, captain.”

Steve headed for the door, but paused with one hand on it, looking back at them. “Hey, how did you all get to the mall anyway?”

El gave a weird little half-smile. “Billy drove us.”

“Huh. …In one car?” And he did _not_ need that disapproving look from Steve Harrington of all people.

**Notes for the Chapter:**

> Steve: Hey bro what do you want to eat  
> Mind Flayer: The souls of the innocent  
> Billy: Ice cream  
> Mind Flayer: No!  
> Billy: Two ice creams
> 
> All hail the sailor suit


	5. Assembly

It only took one look at Will’s pale, drawn face for the group to collectively decide they needed to track down that other monster thing, and fast. Even Billy, who really didn’t know anything about the kid or what had happened, felt a weird protective urge to not let it happen again. Gross. He really had to stop hanging out with Max’s geeky friends.

That said, he wasn’t the most helpful in identifying suspects, mostly because he had no idea what he was looking for. The dorks had given him such extremely useful and specific explanations, like ‘someone acting weird’ or ‘maybe going missing.’ Billy propped his legs up on the table, leaning back in the seat he’d claimed after Steve had vacated it, ignoring the little frown on Dustin’s face at the action.

“Maybe if we knew more about what the Mind Flayers wanted – or what makes this one so different – we’d know where to start,” Mike pointed out. “Can you uh… ask it?”

Billy was about to snap that the thing could hear them perfectly well on its own, but paused when it started answering anyway.

**_”The one you knew seeks largely to, hm… invade. Our place in your dimension is tenuous. He would likely seek someone with plenty of connections, as the more people he can infect, the closer he becomes to shaping his own form. It is not about who finds us; we find you.”_ **

“Doesn’t exactly explain why you picked me.” Sure, he’d dethroned King Steve, but they’d _graduated,_ and he wasn’t exactly keeping in touch with Tommy or Carol or any other kid he’d gone to school with; he’d been planning on saving up and getting the fuck out of Hawkins as soon as he could, and these days he rarely talked to many people outside his job. 

**_“I am not interested in creating my own form, nor am I interested in listening to others of my kind when it seems this world has so many more interesting experiences than destruction – like ice cream. Plus, you are far too good of a match. You and I are not so different. We are both… outcasts. Losers.”_ **

“I am not a-” Billy cut himself off with a glance at the kids staring at him trying to parse the one-sided conversation, not particularly interested in telling them his parasite had just called him a loser. “Gee, thanks. Nothing makes me feel more warm and cuddly than being the Mind Fucker’s favorite meat puppet.”

“Mind _Flayer,_ ” Dustin corrected with an exasperated sigh.

“Whatever. Anyway, he said they look for someone with a lot of connections. They infect other people, and make some sort of body for themselves.”

“So like, what, Mayor Kline?” Lucas asked, seeming to put the ‘making a body’ part on the back burner for now.

Max rolled her eyes. “Has the _Mayor_ gone missing?”

“ _Billy_ didn’t go missing. Actually wait, why didn’t you? Did you luck out and get the Mind Flayer that just always wanted to be a lifeguard?”

Billy shrugged, trying to phrase it without repeating the ‘loser’ comment. “I guess? He said he’s not interested in the same thing the other one is. He’s the interdimensional equivalent of AWOL.”

“But the other one would have to be pretty close too, right? You’re sure you didn’t notice anyone else acting weird at the pool?” Mike asked, eyeing him like he might have been hiding the information on purpose.

“Aside from you twerps trying to roast me alive? No, and if you didn’t remember, I was busy acting pretty damn weird myself. But Adam and Lauren seemed normal enough.”

Max bit her lip in thought. “Isn’t there usually someone else who works with you at the pool? That other girl?”

“Oh yeah, Heather didn’t show today. Was probably sick.”

Max gave him a look like he was the biggest idiot in the world, which was completely uncalled for. “We _said_ anyone who might have gone missing! Is she popular? Does she have a lot of friends?”

Billy rolled his eyes. “She was probably _sick_ ,” he repeated. “You can’t just go barging into peoples’ houses accusing them of being possessed because they miss one day of work.”

The kids seemed to consider that for a moment, knowing they couldn’t jump to conclusions but unwilling to give up the closest thing they had to a lead. A bit begrudgingly, the Mind Freak in his head allowed, **_”He couldn’t have gone far without a host of his own. We cannot survive here without them.”_**

“Could still be anyone in Hawkins,” Billy contended. Privately though, Billy reflected that yeah, straight-A, perfect body, lifeguard Heather probably knew a _lot_ of people, and wouldn’t be nearly as conspicuous as someone like the Mayor acting weird. Maybe it was worth looking into. “You can’t tell where the other guy might be?”

**_”Not from so far away.”_** Great. He really had no excuse for showing up on Heather’s doorstep like he was her boyfriend or something, but if it was the only way to know-

“I could try. To find her, I mean.” Billy quirked an eyebrow at El, pretty sure he was missing something here by the way the kids reacted. Mike in particular tensed like she’d just said she was going to throw herself directly into the monster’s jaws.

“You can’t mean-” Mike started, a half-second before Billy asked, “Am I missing something here?”

Max gave Mike a narrow-eyed look, before answering Billy’s question. Sort of. “El has these… powers.”

“Powers?” he repeated dryly.

“She pushes stuff with her mind, and she can find people, who are missing. If she concentrates on them.”

“More like _spy_ on them,” Lucas muttered, only earning himself a withering glare from Max.

Billy’s inner voice was _not_ happy to hear about El’s apparent powers. **_”We should kill the girl.”_**

“ _No,_ bad idea,” Billy insisted, privately wondering why being able to push stuff and spy on people freaked out a guy who from the sound of things could do a hell of a lot worse. But he should probably pick his battles here and focus on not letting the thing murder a child, freaky mind powers or no freaky mind powers. He fielded their curious looks with an offhanded, “he’s not thrilled about those powers of yours.”

The implication didn’t seem to worry El much, and for the first time Billy felt vaguely intimidated by the unassuming girl. “I can do it,” she insisted, “so we know what we’re going up against. Or if we should keep looking. …But not here. Too loud.”

Billy snorted. “If you think I’m driving you around to do some freaky witch shit and getting another judgmental glare for child endangerment from _Captain Steve_ , think again. Ask _him_ to drive you.”

~~

The kids did their best, but apparently Steve took his job as an ice cream salesman seriously enough that not leaving his post outweighed potential supernatural threats. Or maybe it was the glare Robin was giving him that pretty effectively communicated ‘if you leave me here and the girl asking for all the samples comes back you’ll _wish_ for death by monsters’. Which was fair, because that glare was _dark_.

Eventually they moved on to bartering for bus fare, and while Steve didn’t look much happier about the idea of them going off alone, or coughing up enough money for them to ride, he agreed on the condition that they find Hopper and Joyce first, who Billy hoped were actual adults, and let them step in if anything went wrong. Jesus, Steve really did act like their second mom.

Steve begrudgingly fished out his wallet and gave each one fare, but when he held the money out to Dustin the kid shook his head. “Actually, I’m staying here – I’ll keep my radio on so you guys can tell us if you learn anything. And somebody’s gotta keep an eye on Billy.”

Billy tossed him a sharp-toothed smile, just because he could, and he might be tolerating these kids for now but that didn’t mean he had to _like_ them. Dustin’s half-step back was pretty satisfying.

Money in hand, the rest of the kids left _Scoops Ahoy,_ Steve watching them go with a worried little frown. Billy shifted uncomfortably, wanting to wipe the frown off his face, thinking of _one_ way and immediately discarding it. Now that the kids had left, this was… awkward.

His thoughts were thankfully derailed by knocking coming from what sounded like the break room. Robin straightened from where she’d slumped on the wall, seeming to look between him and Steve with before chirping a quick “delivery!” and slipping back into the room.

Billy cleared his throat, opening his mouth to say _something - ‘sorry for breaking a plate over your head, can we start over, that sailor suit really leaves nothing to the imagination’ -_ but before he could, Steve gave one glance to the closing door and half-whispered, “What the fuck are we going to do about the Mind Flayer inside you, Hargrove?”

Right. More important things to deal with right now. “How the fuck should I know? I’d love it _out_ of me, but if that means another attempt to _cook_ me in a sauna, I’ll keep the damn thing.”

Dustin, who’d moved closer to join their semi-circle of secrecy, barely smothered a snort of laughter. “ _That_ was their test? Well, apparently Will’s came out with a hot poker, so I guess you’d have gotten the better end of the deal if it worked.”

**_”Stick me with one of your ‘hot pokers’ and die, tiny human.”_** Billy didn’t agree with the guy on much, but he could definitely agree with that. And really, aside from trying to keep a leash on how much ice cream he ate or extending his workout routine to compensate, the guy hadn’t done anything so bad Billy wanted him out more than he didn’t want to be fucking branded.

They were interrupted by Robin bursting back into the room, wide-eyed in excitement. “Silver cat!” she shouted, looking way more keyed up than the phrase should have deserved.

Steve was similarly slow on the uptake, staring blankly at her. “What?”

“The delivery company – Lynx Corp. _They’re_ the silver cat from the Russian code! Something’s happening under the mall, just like you thought. Something big. And it’s connected to the deliveries.”

Steve gave Billy what he assumed was supposed to be a meaningful look, as he repeated, “It’s got to be connected.” Billy really didn’t understand why all this Upside Down shit would be connected to whatever Russian code they were talking about, but admittedly he knew way less about this stuff than Steve seemed to.

Robin vaulted over the counter – damn, that girl could move – and out the door, looking around like a crazy person and mumbling, “a trip to China sounds nice” under her breath, and Billy started to question whether they’d just sent the kids on a wild goose chase because he was pretty sure he spotted someone acting strange right _here_. The three of them exchanged confused glances before following.

“Robin, what are you doing?” Steve asked her, looking up at where she was now standing on top of a food court table.

She leaped down, landing effortlessly on the balls of her feet. “I cracked the code.”

“Does anyone want to tell me what the fuck she’s on about?”

**Notes for the Chapter:**

> I keep thinking about giving the different Mind Flayers D&D-based nicknames to differentiate them, but I know extremely little about D&D so that’s proving a bit difficult. Apparently, as I learned after writing most of this chapter (and having to scratch a few lines as a result), variants like the Arcanist were not really introduced for many years after ST takes place, so using the variants as nicknames seemed a touch too immersion-breaking. If someone well-versed in D&D in the 80’s has suggestions, I am all ears.


	6. Trials

Dustin paced the back room of _Scoops,_ binoculars hanging loosely from his hand. “The keycard opens the storage room door, but unfortunately the Russian with the keycard also has a massive gun. Whatever’s in those boxes, they really don’t want anybody finding it.”

“But there’s gotta be a way in,” Robin countered.

**_”We could simply kill the guard.”_** Billy frowned, about to voice the objection that creating a murder scene right outside the mall might be a bad idea, but before he could Steve chipped in with his own idea.

“I could just take him out.”

Billy snorted a laugh behind a clenched fist, and he shouldn’t laugh, Steve was trying to impress Robin and laughing was probably a dick move but he couldn’t help it. Steve gave him a dark, betrayed look.

Dustin seemed similarly unimpressed with Steve’s bravado. “Did you not hear the part about the massive gun?”

“ _Yes,_ Dustin, I did. That’s why I would be sneaking behind him and then knocking him out.”

“Then tell me this, and be honest, have you ever actually… _won_ a fight?”

They both looked over at Billy, who abruptly stopped laughing, raising a hand to the back of his head self-consciously. To be fair, he really didn’t think being injected with some kind of drug and threatened with a nail bat by your step-sister counted as winning either, but he couldn’t deny the beating he’d given Steve before that.

Robin picked up on their glances and her eyes widened. “Wait, the reason you came to class looking half-dead for like a month was because _Billy Hargrove_ beat the shit out of you?” And oh, he was undeniably a little surprised Harrington hadn’t told everyone he could about who had been responsible. What had he said instead? Or had anyone even asked?

“That was _one_ time!” Steve protested, and Billy wasn’t sure if he was trying to suggest he wouldn’t lose again (he would, no contest, even without the Mind Fucker) or that Billy wouldn’t do that again (he wouldn’t. He really wouldn’t).

“Twice,” Dustin cut in, and Billy raised an eyebrow because who the fuck else was pretty boy Harrington getting into fist fights with? “Jonathan. The year prior?”

“ _Jonathan_ beat you up?” Billy guffawed, and yeah he was back to laughing, because _seriously? Jonathan?_ The kid who not only looked like he’d blow over in a stiff breeze, but ended up with Steve’s girlfriend, and now sat with them at lunch? _That_ Jonathan had gotten the jump on Steve, and Harrington still thought he could bluster about taking down a Russian guard?

He glanced at Robin, and found her looking back at him just as amused as Harrington and Henderson continued to bicker to each other. But a beat later her eyes tracked a little behind and above him, and Billy spun to see what she was looking at, seeing only the wall and the air vent.

When Robin suddenly leaped out of her seat, grabbed a fistful of tips, and shouted something about Steve not getting beaten up while she was gone, he had just as little of a clue what she was on about as the rest of them.

~~

When El put on the blindfold and sought out Heather, the black space felt colder than usual.

There was nothing around her at first, just the darkness, and a chill that made gooseflesh rise on her arms. She forced herself to take stumbling steps forward, trying to stay concentrated on looking for Heather. She kept walking until she heard something that sounded like… crying?

A flash of red broke up the blackness, and El saw a crumpled form on the ground, someone leaned forward with their head on their knees and arms wrapped tight around their legs. El approached cautiously, listening to the girl cry, and softly asked, “Heather?”

The girl in the red swimsuit – Heather, it had to be her – choked off a sob and looked up at her. “Wh-who are you?” she asked, eyes wide and glistening with tears.

“I’m El.”

“El. Where are we?”

El gulped. “I don’t know. It doesn’t usually stay like this.”

Confusion flicked across Heather’s face, replaced just as quickly when tears spring to her eyes again. “Please, help me get out of here.” She stretched a trembling hand up, and El grasped it, leaning backwards to pull her up – but the girl didn’t budge. “El,” Heather repeated, and slowly the hunted look in her eyes started to fade. “It’s so nice to finally know your name.” A sharp smile flashed across her features and she _yanked,_ El taking an involuntary step forward at the sudden weight on her arm, thrashing in the grip.

“Get off! Let me go!” But Heather’s grip was tight, even as she seemed to sink into the floor of the dark space, trying to tug El down with her. Dark lines like veins crept up the sides of her face with the effort. For a brief second, the space around them seemed to lighten, and El recognized a barely-there version of the Byers’ living room, but she forced the sight away, _shoving_ outwards with her mind and finally breaking free of Heather’s hold. The girl went wide-eyed, falling through the floor, and El’s eyes jolted open, back in the real world.

“El!” Mike was yelling, holding her gently but looking panicked, and she focused on his face, trying to put Heather’s out of her mind. She relaxed into his arms and thought, not for the first time, that she _really_ wished Hopper or even Mrs. Byers was here. The house had been empty when they’d showed up and Hopper hadn’t answered the phone, and knowing the Mind Flayer from last year was out there, she just hoped they were safe.

“What did you see?” That was Max, crouching right behind Mike, eyes full of concern but also serious.

“It… it’s in Heather. The other Mind Flayer.”

~~

“Alright, this isn’t working.”

From where he was leaned against the wall watching Steve try to push Dustin into the air ducts, Billy had to agree. Dustin, halfway in the duct, shouted “ _touch my butt I don’t care!_ ” and Billy _really_ hoped whoever was ringing that fucking bell at the counter wasn’t close enough to hear that.

Speaking of, Robin was giving that girl a look like she was about to shove her in the ice cream maker. Or get her involved in this mess. For the girl’s sake, Billy thought as Robin left the break room, he really hoped it was the former. Billy followed, if only to escape what had devolved into Steve and Dustin snapping at each other and making no progress on the vent.

Now that he was out front, Billy was pretty sure he recognized the girl from picking Max up a few times. “Hey wait, aren’t you Lucas’ sister?”

“And aren’t you _not_ the sailor boy who works here? I didn’t come here to talk to my idiot brother’s girlfriend’s idiot brother. If you’re going to stand behind the counter, you can at least make yourself useful and scoop ice cream.” Right, that was why he’d never gone inside to fetch Max at the Sinclair’s. Among other nail bat-related reasons. Maybe he should go get Steve and Dustin after all.

There were a few minutes of ice cream-based haggling (and Billy sneaking bites of whatever was left behind), but they’d produced a fairly workable plan of Erica getting into the air vents and opening the doors to the secret room from the inside. Well, workable if you didn’t count Erica’s demands for free ice cream for life, which Steve still looked grumpy about, even now that the mall had closed and they were up on the roof, Robin fielding Erica’s snarky comments from the radio.

“Hey, where’s _my_ free ice cream for life for helping you out with this shit?” Billy groused.

Steve grinned at him, self-satisfied. “Sorry Hargrove, should have negotiated when you had the chance.”

Billy laughed. “The Mind Fucker doesn’t seem to think he’s got to negotiate for anything.” Said Mind Fucker made a rumbling noise of agreement.

“Well he just might be right there. I only make three bucks an hour, and that is not enough to risk my life guarding ice cream from the Mind Flayer.”

**_”I prefer Mind Fucker._** ” A man of good taste. None of that nerd shit. “He said he prefers Mind Fucker.”

“He did _not,_ ” Steve protested, holding back a laugh.

“Would you two _focus_ ,” Robin groaned, and Steve gave Billy a wry ‘uh oh, we’re in trouble now’ look which he bit his lip to not laugh at.

“I’m in,” Erica’s voice crackled over the radio, followed quickly by the door sliding open. “Free ice cream _for life,_ ” she reminded them, but as they all scrambled down from the roof even Steve didn’t seem to mind.

They slipped inside, gathering around one of the boxes, while Steve cut through the tape and opened it up. Inside were four cylindrical canisters, each one containing some kind of nasty green slime.

“What the fuck is that,” Billy hissed under his breath, but either the Mind Fucker didn’t know or didn’t see fit to enlighten him. Instead, the only answer to his question was a sudden rumble and shake of the floor underneath them. 

“We should go,” Robin decided, grabbing the green stuff from Steve and making for the door. Dustin pressed the button for the doors, but nothing happened.

“Just press the damn button nerd!” Erica snapped, and yeah, Billy felt much the same way.

Dustin slammed his hand down again, then repeatedly, but the doors remained shut. “It’s not- it’s not working, nothing’s happening!” 

Steve moved to push Dustin out of the way, trying to get a look at the panel himself, while Billy muttered “I’ll open the damn door myself,” figuring that if the Mind Fucker had forced his way out of the locked sauna room before, it could probably help him turn an automatic door into a manual one. Before he could, a wall slammed down in front of the doors, and the floor beneath them gave another gut-lurching shake before dropping out beneath them entirely.

Billy slammed himself up against the newly-formed wall as the room – no, the _elevator_ \- dropped. He locked eyes with Steve, who wasn’t screaming like Erica, Robin, and Dustin were, and simply offered an “oh, shit.”

Then the elevator _really_ picked up speed, and now they were _all_ screaming as they hurtled downward, pressed against the sides by the force, trying not to think of what exactly would meet them at the bottom.

**Notes for the Chapter:**

> Me: It’s been less than a day since I posted the last chapter  
> Also me: What if I posted the next one Right Now though
> 
> We’re getting into what I’d consider the “meat” of the story now, and most of my planning and outlining is done, so updates may be slightly more frequent from here. This fic is quite a bit longer than I had initially envisioned (definitely in part as a result of your lovely comments and interest in it), but that just means I’m gonna have to write faster to finish in a reasonable amount of time lol. 
> 
> Re: my last endnote on nicknames, as I don’t know much about D&D-sourced ones, that idea may either get scrapped or only used when the kids are referring to the different Mind Flayers, since it hasn’t been set up by them yet and it’d probably be a bit odd to happen now. Instead, as you might have noticed this chapter, it was suggested (and I def agree) that Billy’s inability to get the MF’s nerd-sourced name right would lead to him calling it the Mind Fucker. The poor Party, they just can’t make Billy put up with their nerd shit the same way Steve does.


	7. Quarantine

The elevator slammed to a halt abruptly, sending them all sprawling to the floor. Billy slapped a hand at the wall behind him, trying to leverage himself up to get his legs back under him, and glanced over at where Harrington was struggling out from under some of the boxes that didn't happen to be filled with green slime. What the fuck had they gotten him into exactly?

Robin and Steve bickered about a keycard, and Billy cut them off with a “so we’re stuck then?”

Steve whirled on him, hands threading into his hair. “Yeah, yeah Hargrove, we’re _fucking stuck_. I’m going to die 50 feet underground in a Russian base with my coworker, two children, and Billy fucking Hargrove.”

**_”He seems stressed.”_ **

“I’m stressed too asshole!” Billy snapped, and Steve frowned, probably assuming the comment was for him. “Fuck, not you, him!” Billy sighed with an impatient twist of his wrist towards his head.

**_”Only attempting to help,”_** the Mind Fucker said, sounding _smug,_ the bastard.

“Not helpful.”

Robin blinked at him. “Steve why’s your friend here talking to himself?”

Steve gave a little unconcerned hitch of his shoulders. “Oh yeah, he’s got some kind of interdimensional parasite thing, don’t mind him.”

Billy blinked in astonishment, because _seriously?_ And then squinted an eye in annoyance as said interdimensional parasite started bitching about being called a parasite again.

To her credit, Robin only seemed completely thrown for about a minute, which was way less time than Billy would have needed with Steve’s idea of an explanation. “…Whatever, fine, I’m just gonna accept that, because Russians having a secret base under the god damn mall wasn’t weird enough for today.” And that was that, apparently. Jesus, this chick was unreal. He was a little impressed.

“Guys,” Dustin broke in suddenly, pointing a finger towards the ceiling. “What if we climbed out?” Billy tracked the movement to a hatch in the ceiling of the elevator, and figured that while they probably wouldn’t be able to do much climbing, anything that got them out of this damn enclosed space would be better than nothing.

Billy shoved the hatch open and leveraged himself out, leaning back to offer a steadying hand to Steve and Dustin as they followed. Unfortunately the elevator shaft wasn’t much better than being in the elevator itself, something Steve confirmed when he stared upwards at the stories of cable stretching back to the surface and muttered, “What were you saying about climbing?”

Dustin gave a disappointed sigh, sitting down with a huff. He had something in his hand – one of those little radios? – and was fiddling with the antennae. It crackled to life in his hand, and Dustin leaned forward to try, “This is a Code Red, I repeat, a Code Red, does anyone copy? There are innocent children trapped in the Starcourt mall. The Red Army has infiltrated Hawkins, and if we are found, they will kill us.”

The first time he did it, it was almost a little endearing. Eight hours and some pretty shitty sleep later, it had become dramatically less so. Billy growled. “Kid, if you say that one more I’m gonna shove that antenna up your-”

“Alright, alright, Jesus,” Dustin snapped, folding the antenna up again. “I don’t think anyone’s close enough now anyway. I just thought, since the mall just opened…”

Steve, who’d slid down to sit with his back against the same wall as Billy, let his head fall back into said wall. “Save your battery,” he suggested. “And keep it down? We don’t want the _Russians_ to hear your little code either.

Dustin rolled his eyes, countering, “Right, and not so you can continue to spend the night with _Robin._ ”

Billy grimaced, even as Steve deflected, “Would you quit it with that creepy shit? Nothing’s happening. We were trying to get ourselves out of here.”

Despite himself, the corner of Billy’s lips twitched up. “You get stuck in an elevator with a girl and you _still_ can’t get a date? What happened, Harrington?”

Steve reached out a hand to shove his arm. “Fuck off Hargrove, didn’t see you making any moves either.”

Dustin, who looked seriously disturbed by the idea of _Billy_ with Robin rather than his precious Steve, took this as his cue to leave, slipping back down into the elevator, leaving just Billy and Steve. Alone.

Billy’s gut roiled, and wasn’t it funny how he’d gotten himself possessed but Steve Harrington was the only one who could make him _nervous_. “This blows,” he said, for lack of anything else to fill the silence.

“Understatement of the year,” Steve agreed.

**_“You feel sad, do you not Billy, when you’re with him.”_ **

“Get out of my head asshole,” Billy grumbled. Steve barely looked over at him, and Billy wondered when they’d both gotten so used to Billy talking to the voice in his head.

The Mind Fucker didn’t give up quite so easily. **_“You never apologized… you may not live to get another chance.”_** And wasn’t that a comforting thought.

“Listen, Harrington…” and this time Steve did turn to look at him, “for what it’s worth. I’m sorry about that night at the Byers. Wasn’t right of me. And… for everything else. I’m sorry.”

“Billy…” Steve’s stare faltered, and abruptly he turned to glance towards the sound of… some sort of car? “Now’s really not the time, let’s just get out of this elevator, okay?”

**_“Aww, that’s nice.”_ **

They both got to their feet, scrambling back down into the elevator. Robin had an ear pressed up against the doors, muttering, “we’ve got company.” The sound of the vehicle grew louder.

Bill hissed a quiet “ _Hide_ ” before grabbing Steve by the back of his uniform, hauling him back behind a stack of boxes and motioning for the other to do the same. If someone was coming to open the doors, that was their chance to finally escape the damn elevator, provided they weren’t spotted first.

Everyone held their breath as the whirring of wheels came to a halt, and the door slid open. The men who entered went right for the stack of boxes in the middle, thankfully leaving the stacks of empty decoy boxes untouched. Now they just had to figure out a way to keep the doors open…

Next to him, Steve nudged Erica’s shoulder, gesturing to the canister of green shit in her hand with increasing urgency until she finally handed it over. They all waited, tense, until the men loaded back into the cart and drove off, door slowly shutting behind them. Steve launched himself forward, leaning under the closing door to wedge the canister in place, and _oh_ , yeah, that’d work.

Maybe not for long though. Steve waved Dustin and Erica through first, and Robin followed as the groaning of the door grew louder and hairline cracks spread over the surface of the glass container. Time to go, then. Billy slithered his way under the door, then turned to watch Steve do the same.

His heart leapt as the glass gave another crack, this one much louder. Steve was going to get cut in half. “Alright, hey Mind Fucker, a little help?” Billy hissed under his breath, then dove forward, sliding his hands under the door and _pulling_. The door protested with a shriek of metal, but Billy only gripped harder, panting with the effort even with the Mind Fucker’s strength. Steve scraped clear of the door, just in time for Billy to release his grip. The door slammed downwards, shattering the vial and releasing the green slime inside, which hissed as it ate its way through the floor.

They stared in mild disgust for a beat – well, _most_ of them did. When Billy turned, Harrington was staring at _him,_ wide-eyed and flushed. “You okay?”

Steve seemed to shake himself, refocusing. “Yeah, I’m uh- I’m alright. Thanks. For that.”

“Holy mother of God,” Dustin yelped, and they all turned to stare down the seemingly-endless hallway. So they weren’t out of the woods just yet it seemed. 

Surprisingly, it was Steve who started leading the way down the hall. “Come on, let’s go,” he pressed, studiously not looking behind him. Billy shrugged and followed.

~~

The Party woke up to the sound of the front door of the Byers’ house slamming shut. After what they’d learned yesterday, none of them had been too keen to head home for the night, made all the worse by Mrs. Byers not coming home. Max wondered if that door had been her, but when she blinked sleepy eyes at the burry form, it was Will’s brother, Jonathan. And, a half-step behind him, Nancy Wheeler.

Will was wide awake in seconds, and some tension seemed to leave Jonathan’s shoulders at seeing the kid. “There you are,” Jonathan breathed. “Look, I hate to be the one to say this but-”

“We’ve got a problem,” Will interrupted, taking the words right out of Jonathan’s mouth. “I know.”

A few seconds of shuffled papers spread out across the coffee table later, Nancy was frowning down at what looked like medical records. “It was the same thing, the exact same thing that happened to Will last year. And look at the readings.” She gestured with a sweeping hand at the temperature readouts, which dipped well below normal range.

“He likes it cold,” Will mumbled, voicing their concerns.

“It doesn’t make any sense though,” Max protested. “We already _know_ the Mind Flayer’s in that lifeguard Heather, and the other one’s in Billy. How many of these things are there? And why aren’t they acting the same?”

Nancy yelped a startled, “Heather Holloway?” just as Jonathan asked a similarly-toned “your _brother?_ ” Then they blinked at each other, and said in tandem, “There’s _two_?”

“It’s… a long story. We’ll explain, but for now, it’s the one in Heather we’re worried about.”

Mike nodded, looking just as confused as she felt. “El tried to find Heather last night, around nine.”

Nancy looked at him sharply, adding, “That’s the same time all this happened to Mrs. Driscoll. So they’re connected!”

On Max’s left, El’s brows drew down in concentration. “The other Mind Flayer, the one in Billy, he said… he said people would be _infected_.”

Max nodded, something settling cold in her gut at the implication. “And last year, Will wasn’t eating chemicals like you said Mrs. Driscoll was, right? Maybe there are just two. Maybe Mrs. Driscoll is just… infected.”

“Flayed,” Mike added.

“Wait,” said Nancy. “If Heather _Holloway_ is the Mind Flayer, then…” she looked at Jonathan, and both of them said, “Tom.”

Max didn’t know who Tom was, but from the looks on their faces she had a feeling this flayed stuff was just the tip of the iceberg. 

As they headed to the car, Nancy added, “and you’re going to explain how Billy Hargrove got involved in all this on the way over!”

**Notes for the Chapter:**

> Steve: the gay thoughts can’t catch me if I walk down this hallway fast enough


	8. Breach

“The com room is right through that door,” Erica insisted, a half-whisper half-shout from where they’re crouched behind the bend in the hallway.

“Then we just have to sneak through this room full of Russian guards to get there,” Robin said with a wry twist of her lips.

Steve snorted. “Been working for us so far,” he pointed out, and Billy was, surprisingly, inclined to agree. He’d expected much more trouble trying to go undetected, but the echo-y walls and cavernous hallways actually provided some pretty good warning for oncoming Russians, and plenty of places to hide. It’d be difficult to cross the room, but not impossible.

Billy gestured with a flick of his head towards the shadowed wall and pressed himself against it, edging their group around the flurry of motion at the room’s center. He paused to avoid any stray gazes, then quietly ushered the rest of them forward and through the door.

It was only once they’d gotten inside, Steve still hanging onto the handle to slow the closing door’s momentum, that Billy realized they’d fucked up. There was a guy in the control room, and they’d already been spotted. Billy’s hands fisted automatically, and he shifted his stance for a fight, but before he could Robin had raised a placating hand toward the man and was saying something in Russian.

The guy looked at her, obviously confused, and abruptly decided they weren’t who they claimed to be. His hand sought the gun at his hip, and Billy tensed-

From his right, Steve loosed a guttural scream and flung himself forward, crashing into the Russian and sending them both sprawling back against the big radio. Billy, who’d been a half second from throwing a punch, now found himself only blinking in surprise and something like awe as he watched Steve wrestle away the gun, get tossed into a control panel, and bring a microphone down on the Russian’s head. The man collapsed to the floor, and Steve took a staggering step back, breathing heavy.

“Holy shit, Harrington,” Billy said under his breath, and definitely did not get distracted by how extremely hot Steve had looked saving their asses. Well. Okay, maybe he got a little bit distracted.

“You actually won a fight!” Dustin cheered, and Billy gratefully took the excuse to catch his breath. He shouldn’t be thinking that way about Steve, no matter how good his dumb floppy hair looked all tousled in front of his face, standing there in that stupid sailor suit rumpled from the scuffle.

Billy carefully tamped down on those feelings, because now really was not the time, and tried to compensate with his usual brand of sarcasm. “Looks like somebody finally learned to plant their feet.” And shit, he thought, wincing, that was probably a little bit closer to ‘douchebag’ than ‘sarcastic,’ a shade too near the Billy who’d shown up at the Byers’ already hoping for a fight, but if any of that registered to Steve it didn’t show when he grinned back at Billy wolfishly.

 _Jesus._ **_”Oh, I like this one.”_** His thoughts exactly.

The rest of the room faded back in as Billy remembered they should probably get moving before anyone else came to check on their comrade. He was about to suggest as much when Robin interrupted, “Guys, there’s something up there,” gesturing to a stairway that seemed to glow a faint blue behind her.

They headed up the stairs and pressed themselves against the glass in the doors, hardly noticing the room of scientists and controls. Billy’s eyes were drawn directly to the huge, drill-like structure in the center of the room, and the giant crack on the wall the drill seemed to be focused on.

His breath stuck in his throat. **_”That,”_** the Mind Fucker clarified, even though Billy somehow _knew_ without him saying, **_”is the gate I came through.”_**

“You and… the other one?” Billy asked, though he didn’t particularly want to know.

He liked the answer even less than he’d expected. _**”I came this time. Drawn by him. He was already here.”**_

“And they’re trying to keep the gate open. We are so fucked.”

~~

Trying to explain that machine was already not going to be fun, but because the universe had it out for them, that was the exact moment alarms started blaring. They couldn’t go back the way they came, too many guards, which meant they had to go through the drill control room. Billy started towards it, only pausing a brief second when Steve protested, “we can’t go that way!”

“You see any better options around here, Princess?” Billy bit back over his shoulder, even as he was slamming the door open wide. Scientists spun in a panic, but at least they didn’t have guns, not until floods of guards filled the room, hot on their trail. They hit a dead end mere feet away from the pulsing lights and heat of the drill, and Billy launched himself backwards, not eager to come anywhere near that thing if he didn’t have to.

A guard stood blocking the stairs, and Billy hissed a quick, “definitely gonna need some help with this one,” but the Mind Fucker was already on board. His shove sent the man toppling over the railing, and left thick trails of black sludge across the guy’s uniform. Billy blinked down at his hand, which was covered in the same black veins he hadn’t seen since he’d first looked in the mirror, and figured the Mind Fucker must really be about as desperate to get out of here as he was if he’d dropped whatever act had been keeping Billy looking normal.

They sprinted through the base, shoving barrels and slamming doors behind them, trying to get enough distance that they might be able to hide somewhere. Steve pressed himself against the heavy metal of the door they’d just shut, leaning his weight against the pounding of Russian guards on the other side. As the door jumped underneath him, Robin shoved herself up against it as well, but they were fighting a losing battle, until Dustin pulled open some sort of hatch and yelled “down here!” and then he and Erica were disappearing through it.

Billy took a step back towards Steve and Robin, meaning to help them with the door while they escaped down the hatch, but his body froze. He strained against the force, but couldn’t make himself move. “What the fuck?” he snarled around gritted teeth as instead of moving towards Robin and Steve, his body took steps towards the hatch, completely outside of his control.

**_”We have to leave. They cannot catch us.”_ **

“I’m not _leaving_ them,” Billy protested, even as his body did exactly that. If something happened to Steve, or even Robin who he’d started to warm up to, and he could have saved them but didn’t, he wouldn’t have been able to live with himself. 

But nothing he did changed his course. The Mind Fucker snarled impatiently at his attempts, but that guy was an asshole and evidently a coward and he could go fuck himself. **_”We have to LEAVE,"_** he insisted, as Billy’s body dropped down into the hatch, slamming it shut behind him just as the door to the room burst open and Russian guards flooded inside.

Dustin jumped, clearly surprised to see him there. “You _left_ Steve?” he yelped, wide-eyed. “How could you leave Steve!” But Billy had no answer for him, other than to shove him roughly forward and just keep moving.

Control slowly ebbed back to him as he fled with Dustin and Erica, but it was too late to head back now; not that he had any delusions about the Mind Fucker letting him do so in the first place. Frustration filled him, made him clench his jaw and squeeze his hands into fists and want to punch something but they had to keep _moving_ so he didn’t, even as he lagged a few paces behind Erica and Dustin.

“You’re a fucking coward,” he snarled at the Mind Fucker, “a fucking coward and a douchebag.”

The Mind Fucker gave a dismissive snort. **_”Maybe so. Maybe I have always been, and that is why I did not seek the one your friends called the Mind Flayer. I was not willing to risk my own life for his schemes, and I am_ certainly _not risking our lives for the sake of two humans. Even those two.”_**

“Fuck you,” Billy bit back. “I’m figuring out how to get you the fuck out of me first chance I get, and then I’m going back for them, since you’re too much of a bitch to do it.”

The Mind Fucker’s tone abruptly grew dark and serious. **_”You don’t seem to understand the situation you’re in. I_ let _you have control, and when I need to I will take it back. You do not have a say in the matter. Cooperate, and you might just survive. That is the deal.”_**

“Pretty shit deal if you ask me.” But the Mind Fucker _wasn’t_ asking him, that was half the problem, so they just trudged down the rest of the cramped tunnel in silence, Billy trying hard to ignore the betrayed glare Dustin kept casting over his shoulder. Didn’t the kid know he hadn’t wanted to leave? Hadn’t he heard it wasn’t his fault?

But, of course, it was. Just another primo screw up to add to the tally of Billy Hargrove’s endless list of screw ups.

Eventually they slowed and paused, trying to gain their bearings. The tunnels down here were really just giant air vents, punctuated by equally giant whirling fans, and after their mad scramble through the base they didn’t have much idea where they were now. “If you’re done talking to yourself,” Erica said with a pointed glare, which Billy did his best to ignore because the girl might play tough but she was like eight and they were on the run from Russians with guns so a little defensive sass was probably warranted, “we need a plan to get out of here.”

“And to go back and rescue Robin and Steve!” Dustin insisted.

Erica gave a gusty sigh, but relented with no argument. “Fine, but they’re gonna have to find something better than ice cream to repay us with this time. Let’s just focus on getting _up_ for now, and worry about getting _out_ once we’re not down here in the air ducts.”

Billy agreed, not quite so appreciative of the reminder of just how far underground they had to be right now. “If there are fans down here, they have to connect to the other floors somehow. It’ll be just like the vents you crawled through to get to the elevator, except hopefully a lot wider.”

“And without a map,” Dustin pointed out. “Which means we’ll just have to pick one of these vents at random.”

Billy frowned at the shiny metal corridors, chewing thoughtfully at his bottom lip. “Well in that case, anybody feeling lucky?”

After a short debate between Dustin and Erica (despite the fact that _neither_ of them had any idea if their chosen fan was the right one), they made up their mind. Dustin felt along the wall next to the fan, muttering, “There’s gotta be wires here somewhere, if I can just find them I can stop the fan-”

Billy rolled his eyes and reached his hand into the fan, grabbing one of the blades and easily stopping its rotation. He pulled and the blades tore from their bolt with a shriek of metal, clanging against the floor when Billy dropped it. “Or we could just do that,” Dustin corrected himself, shrugging before following Billy into the vent.

Unfortunately, their choice hadn’t been lucky enough. They’d climbed through the vents without any issue, but they hadn’t taken two steps on the upper level – and into another sort of lab - before thundering footsteps approached, heralding about a dozen Russians with guns trained on them. Billy nudged the kids behind him and eased his hands into the air, watching as they did the same, before he felt his arms forcibly pulled down against his sides. **_”What are you doing?”_**

“Raising my hands, idiot,” and though Billy tried to keep his voice down, heat still crept into it. He was definitely not thrilled at the Mind Flayer overriding him again. 

He forced his hands back up, only for them to be pulled down again. **_”You are making us look bad.”_**

“Yeah? Then _do_ something about it this time, you fucking coward.” After all, they didn’t have much opportunity to run this time. It was fight or surrender, something which the Mind Fucker seemed to understand as it directed his body to lash out at the guards, sending guns flying and tossing guys into walls and Jesus, had he just punched _through_ that guy?

Billy was feeling pretty damn good about their odds this time, until heat crept along the back of his neck, unnoticeable at first but steadily growing warmer. Before he knew what was happening he was growing slick with sweat, sluggish with the sudden heat, and felt the Mind Fucker’s hold on him slipping tenuously. And yeah, maybe before he’d said he was going to get the asshole out of him first chance he got, but right now was _not_ the best time.

He slammed to his knees, hands suddenly shaking, even as Dustin and Erica yelled something he couldn’t focus on behind him. One of the guards moved forward and hit him with something white-hot and electric and he _screamed,_ feeling an awful tearing emanating from the point of contact and throughout his body until something tore _loose_ and he choked on something that spilled from his mouth to puddle on the ground in front of him. Finally the sickly burning feeling faded and the pain pulled away. Something electric cracked near where it had been, and Billy turned to see some kind of cattle prod or some shit, sending sparks flying. He didn’t have much time to focus on that because his attention was drawn to the black puddle of sludge creeping across the floor, just like what had hit him that night in the car. They’d _torn the Mind Fucker out of him_.

He tried to raise an arm toward the black goo but the limb only trembled weakly, still shuddering with electricity and drained from the separation. He could only kneel there and watch as one of the Russians slammed down some kind of glass container on top of it, like the ones that had been holding the green goo from before. The Mind Fucker – and god was it weird thinking of an overhyped puddle of motor oil as that living, talking being that had been inside of him - writhed and slammed against the glass walls to no avail.

When a fresh wave of guards entered the room, hoisting Billy up by the arms and dragging the protesting kids behind him, he couldn’t even get his legs under himself to fight back.

**Notes for the Chapter:**

> ..Oops?
> 
> Slightly longer one this time! I had a lot of ground to cover in this one, and hopefully I did it justice. We’re quite a bit off from canon’s script now, but hey, that’s where the fun happens right?


	9. Resistance

The hiss of TV static crackled behind El as she retied the blindfold, returning to the dark space again. Despite her earlier bravado to Mike regarding trust, her breath hitched a little when she saw Heather again. Now that they knew what this Mind Flayer was doing, had seen the horrible mass of flesh and muscle it had shaped for itself at the hospital, looking into Heather’s smiling face was a lot harder to bear. She did it anyway, because she _had_ to, for her friends.

“Heather,” she said, and Heather’s back stiffened a little, “I want to see. Show me what happened.” Heather’s pleasant smile turned cold around the edges, just as it had before, but El was ready for it this time. She had overpowered the Mind Flayer before, she knew she could do it again-

Heather took El’s outstretched hand in a punishing grip. “We’d like to see too.” El felt off-balance as the black space tilted and swam around her as if the floor itself were moving, and then she was falling, sliding backwards until she was back in the Byers’ living room – alone, save for Heather.

El tried to force it away, to return to the black space, but the room didn’t so much as waver. Heather examined the room with a teasing little smirk on her face. “So this is where you’re hiding out? Hm… can’t be too far away.”

El gritted her teeth and reminded herself that Heather had probably never seen the inside of the Byers’ house before. Maybe that would buy them some time, so long as she didn’t let anything else slip. She could still try to get information out of this. “What are you doing? With the people at the hospital, and the chemicals?”

Heather smirked. “Wouldn’t you like to know,” she teased, pacing a step closer to El. “Not that there’s anything you can do about it.”

Quelling her fear, El stood her ground. “The other one, he said you were _infecting_ people,” she pushed.

“ _Other one,_ ” Heather repeated, and El winced. She hadn’t meant to bring up the one inside Billy. “I _thought_ I noticed someone come through that gate – and giving away trade secrets as well. Knew he was a coward, but I didn’t think he’d put children in danger like that.” Heather was right up in her face now, leaning in, forcing El to take a step back. 

“He’s not like you.”

“Of course not, he’s a weakling. Always has been. He couldn’t survive more than a few minutes on this side of the gate without a host. Tell me, who drew the unlucky straw there?” At El’s refusal to answer, Heather gave a little giggle. “I guess I’ll find out soon enough. Just as soon as I deal with you.”

She took another step closer. “You shouldn’t have looked for me,” Heather said in a sing-song voice, so completely at odds with the way she loomed over El. “Because now I can see you. You let us in, and now you’re just going to have to let us stay. We’re going to end you,” she promised, “and when you’re gone, and there’s no one to stop us, we’re going to end your friends. We’re going to end…. Everything.”

The Byers’ house fell away, replaced by an industrial looking warehouse and old, peeling signs for a steelworks. What looked like half the town were gathered, pooling in crowds, funneling into a line. At the front a man twitched and jerked before _melting,_ leaving behind the same stuff she’d seen at the hospital, which grew with each collapsing person into a horrible amalgamation that rose from the floor, opened its mouth, and _roared_.

El pushed with her powers harder than she ever had before, sending the thing flying backwards and herself flying upright back in her own body. She scrambled to rip the blindfold off, panting against Mike, who had his arms wrapped around her as she choked out half-sobs. “The steelworks,” she forced out when she’d reaffirmed that this was real, that she was safe again, “The Mind Flayer, the flayed… it’s building a body. And it’s coming for us.”

~~

Steve fucking _ached_. His and Robin’s ill-fated attempt to shuffle over to the scissors had left the two of them even worse off, and Steve’s bruised eye sent sparks of pain from where it was pressed against the floor, even if the cold of the metal was kind of nice. Behind him, where he couldn’t twist his head to look, Robin was making stifled crying noises, and Steve was about to comfort her before he listened a little harder and asked, “Are you _laughing_?”

Robin gave another muffled snort, and Steve rolled his eyes. “I can’t believe I’m going to die in a Russian base with Steve ‘the Hair’ Harrington,” she said, and there was something close to shattering in her tone.

“Yeah, not exactly how I planned I’d go either,” he sighed.

“You remember Mrs. Click’s class?” Robin asked, and the non sequitur threw Steve too hard to answer. “Y’know, Clickity-Clackity, that’s what the band kids called her. It was first period, Tuesdays and Thursdays. You were always late, and you’d always show up with breakfast; bacon egg and cheese bagel. We sat two seats away from each other. I don’t think you ever noticed me.”

Steve swallowed, uncomfortable, because no, he really hadn’t. “You were an asshole,” Robin said like it was answer enough. “If I’d known back then I’d be invading a base of evil Russians with you…”

“You would have helped me pass that class?” Steve asked, a quirk to his lips even though she couldn’t see it. “Yeah, I really was an asshole. But if I wasn’t, you would have had to find some other guy to scoop ice cream and crack Russian codes with.”

“Couldn’t picture any other dingus taking your place, Steve,” Robin said with a little laugh. “Who else could measure up to your standards?”

Steve chuckled, even as he protested with a soft, “shut it.” He considered again that this might be _it_ for them. He really hoped Billy and the kids had gotten out okay. He didn’t know if he’d ever see them again. “I liked scooping ice cream with you.”

“Yeah. I liked it too.”

They were interrupted by the sound of the door swinging open, and Steve gave a pained groan as the chairs were righted and the straps pressed on his ribs. “Now where were you two going?” their interrogator asked, “You might have missed all the fun.”

One of the Russians stepped into Steve’s view with a syringe filled with some weird blue liquid, and Steve squirmed, ignoring the pressure it put on his injuries. “Hey, hey, what the fuck is that? No, come on, wait, wait!” The injection slid home just under his jaw and Steve yelped, trying and failing to flinch away from it.

“This will help you talk,” the one who’d injected him said, walking past him to, Steve assumed, do the same to Robin.

For a few minutes Steve didn’t feel any different. He tipped his head back a little so it pressed against the back of Robin’s, the best approximation of a nudge he could give, and mumbled, “I feel fine. What about you?”

Robin giggled, something high pitched and girlier than he’d heard from her before. “Nope,” she answered, popping the P, “I’m fine too. You gave us the wrong stuff, dinguses!”

She and Steve dissolved into laughter, each screeching “Dinguses!” at the Russians, who were pretty unmoved, and it suddenly struck Steve that whatever they were doing was pretty _not fine_. “Oh, there’s something wrong.”

“Something very wrong,” Robin agreed, then burst into laughter again.

~~

Billy pulled ineffectively at the belt-like restraints the Russians had left him in, barely gaining any slack for his efforts. Across from him Dustin and Erica sat with their backs against the wall, similarly stuck. Though even if he could slip the ropes, he still had the bolted-shut door to contend with, and no Mind Fucker strength to force it open with.

“Pretty shitty time to lose your superpowers man,” Dustin grumbled, watching Billy struggle.

“Yeah? Tell that to the Russians, I’m sure they’ll give him right back,” Billy snapped. “We need to figure out a way _out_ of here, preferably before they show up again.” They hadn’t done much more than lock them in here yet, and Billy could take a beating if it came down to it, but he didn’t expect them to go easy on anyone they thought might have information, even if it was two kids. 

Not to mention they’d been left in what seemed like it was a storage room for those vials of green slime – clearly they didn’t build this place thinking they’d have any uninvited guests – and Billy was not interested in shaking too much and sending one of them flying off the shelves onto their heads. Which was why they really had to figure out some way to escape this room as soon as possible.

Dustin’s eyes narrowed. “Why, so you can leave us like you left Robin and Steve?”

“I didn’t _want_ to-” Billy started, then cut himself off with an audible click of his teeth. They didn’t have time to argue. “Listen. I didn’t help Robin and Steve. It wasn’t my choice, but you’re right. But if they _were_ here, they’d want me to keep you two little shits out of trouble. And while I couldn’t give less of a fuck what happens to either of you,” a lie, loathe as he was to admit it he’d actually warmed up to them a little bit, he guessed almost dying multiple times in a day would do that to you, “Steve would be pretty damn pissed at me if I didn’t keep you two safe.”

Dustin’s glare faded a little around the edges. Erica seemed less moved by his little speech. “If we’re done fighting each other, maybe we can focus on the _real_ enemy here.”

Billy wasn’t flexible enough to slip his bonds, and it looked like the ones on Dustin and Erica were pretty tight as well. The restraints kept their hands tight against their sides, with one strap around the waist and one at the top of their arms, pressed against the shoulders. _Shoulders…_ hadn’t the kid said something about his shoulders back when Steve was trying to force him into that vent?

“Dustin, your bone thing!” Dustin looked at him blankly, so he tried to explain a little better than that. “You’ve been trying to push out at the ropes, to give yourself more slack, right?” Billy asked, knowing he’d been trying to do the same thing.

“No shit Hargrove, I want to get out of here just like you do.”

“Right, but it’s never going to work. None of us are strong enough to force them open. But there’s something the Russians don’t know about, and that’s your weird flexible bones. Try to move _through_ instead of out.”

“Like a Chinese finger trap,” Erica realized. “The more you try to pull yourself out, the tighter it gets. But if you try to pull yourself _in_ …”

“Oh!” Dustin pulled his shoulders in tight and wriggled, and already Billy saw a shift in the ropes that hadn’t been there before. “Might take a bit though – they’re still pretty tight.”

“And we still have to worry about the door,” Erica pointed out.

“The green stuff – we can use it to melt through the door, or at least the area around the lock.”

“And what if they hear us trying to break one of those containers open?” Dustin asked, and Billy noted that he’d already managed to get the bonds around his shoulders up and over his head, and was just working on the ones down by his wrists.

Billy was about to say he was willing to take his chances there, but it was Erica who answered instead. “I can hear the guard’s footsteps from outside – he passes by the door every five minutes and then continues down the hallway. If we wait until he comes to the door again, and figure he walks about three miles an hour, then if we account for how loud we’re going to be and how far the noise travels, we should only have to wait about a minute and a half before he’s far enough down the hallway that he won’t hear it. That gives us somewhere around two and a half minutes to get the hell out of here before he comes back around again.”

Dustin stared at her. “You did all that math in your head?” He grinned wide. “ _Nerd_.” With a final wriggle, the last of the ropes slipped over his shoulders, freeing his hands to yank it the rest of the way off. “I’m out!” With his hands free, he was able to make much faster work of removing Erica and Billy’s own restraints.

Billy reached up to the shelves and grabbed the green goo while Erica leaned towards the door, pressing her ear against it. They waited, hearts in their throats, as footsteps approached, then held their breath as the footsteps continued on down the hall. Even as they faded out of range, Erica stayed near the door, then abruptly said “Now!” and backed away from the door.

Billy swung with all his strength, and the glass impacted the edge of the door with a bang. He repeated the motion, really hoping they’d gotten the timing right and no one could hear the slightly arrhythmic banging, and watched cracks form along the glass. With one final swing it shattered, and Billy made sure to step back even while leaning his upper body forward to melt a hole right around the handle and through the door lock. Once the sizzling of the metal quieted down, he reached through the hole left behind and pulled it open with no resistance.

No time to waste. He checked that their coast was still clear and ran, and didn’t stop running until they found a nice empty room to hole themselves up in, this time _without_ being locked inside.

“I can’t believe that worked,” Dustin said, and Billy was inclined to agree. Still, it’d only be a matter of time before they discovered there was a hole melted through their door. “Now how are we going to get to Steve and Robin?”

“ _We_ are not going anywhere,” Billy said, holding up a stalling hand. “ _You two_ are going to stay here where it’s safe, and _I_ am going to go get my douchebag of a parasite back.” He wasn’t entirely sure if he wanted the Mind Fucker back inside him, not after its little hissy fit about their so-called deal, but he wasn’t sure they had much of a choice if they wanted to make it out of here. It was about the only way he could think of where he had even a snowball’s chance in hell of breaking Robin and Steve out from wherever the Russians were keeping them.

But as soon as they were above ground again, they were going to have a serious talk about autonomy and just what their ‘deal’ was going to be.

“Do you even know where they took that thing?” Dustin asked.

“Yeah, I was watching which way they went with him before they threw us in that room, and I know which lab the Russians brought him to.” With any luck the Mind Fucker would be unguarded – fat fucking chance, of course, but he’d figure that out once he got there.

“Stay here,” he repeated over their protests, shutting the door with finality behind him.

Dustin and Erica turned towards each other. “We’re not really waiting here for him to get back, right?” Dustin asked.

“ _Nobody_ tells Erica what to do.”

~~

Billy stalked down hallways that looked just familiar enough to suggest he was on the right path, keeping near the walls as he went. He retraced the steps they’d taken when the Russians had caught him, though this time he went left at the last turn instead of right, entering a more lab-like area. He’d seen them take that container holding the Mind Fucker this way, and was pretty sure he remembered which door they’d entered with him.

When he spotted it, he frowned at the apparent lack of guards. There were a few scientists heading in and out of the other rooms, just distracted enough that Billy only had to press himself back around the bend of the hallway to avoid detection, but he didn’t see anyone with a gun, either patrolling the hallway or in front of the door. He cursed, a little more wary of a threat he couldn’t see than one he could at least plan for. 

But he couldn’t just avoid the door because he was suspicious, not when the coast was clear like this. He snuck up to the door, turning the handle slowly and peering inside before he entered, trying to avoid a repeat of the com room debacle. But no one else was inside, so Billy entered, noting the little lab space and what looked like it might have been a containment unit for the thing they’d shoved Mind Fucker into. 

It was an elongated sort of tube stretching from the floor to the ceiling, with a curved metal chamber and a heavy looking door in the center. Looking at the dimensions, Billy figured they matched up pretty well with the container they’d put the Mind Fucker in. Which would have been great, except the door to the metal chamber was wide open, and the inside was completely empty.

Had they moved him already? And _where_? How were they going to get out of here now?

“ _Shit._ ”

**Notes for the Chapter:**

> Wow this section of the plot ended up longer than I’d thought. I split what I assumed would be one chapter into like two and a half, so here’s the first of those chapters, with certain daring (kind of) rescues to follow in the next one.
> 
> Would you believe the part of this chapter that took the longest to write was trying to figure out not only a plausible room setup Billy, Dustin, and Erica could have been left in but also the way out of my own escape room puzzle. Advice I can offer in hindsight: establish the way out before you put the characters in, lol.


	10. Recombination

To say Jim Hopper was having a bad day might have been a _slight_ understatement.

Between the not-date with (or without, as the case had been) Joyce, and the Russians, and the wandering through the forest, and the damn cherry Slurpees, he figured he could be excused for being a bit grumpy. Unfortunately, what information he’d gotten out of Smirnoff, or Alexei, or whatever the hell his name was, did nothing to alleviate his darkening mood.

The Russians were trying to reopen the gate. _Had_ reopened it, in fact. And they were half a state away from the kids. It wasn’t the most reassuring news he’d ever received, that was for sure. But they had a way to close it this time – a way that didn’t involve El exerting herself or putting herself in any kind of danger.

Of course, there was no telling what she was currently getting herself into – she’d always had a knack for getting herself into trouble. So Jim was a little hesitant to tell them about the gate. On one hand, he didn’t want the kids to be unprepared; on the other, he didn’t want them putting themselves in danger trying to fight something they couldn’t possibly beat. But the fear that El might stumble upon danger without even knowing it was there, when he could have warned her about it – and the small little twist of a frown she always had on her face when he didn’t tell her the whole truth about something, like she expected him to be better than he was, like she put him on some kind of pedestal he knew he didn’t deserve – was swaying him towards picking up the phone.

He looked at Joyce, who seemed similarly conflicted. “I think we should call-”

“I’m going to call the kids,” she said, then blinked when she inadvertently cut him off. “Oh. Good.” She rose and strode to the phone, and Jim followed, watching her dial her house’s number and hoping the phone was loud enough that he could overhear.

The answering “Hello?” that picked up came from someone older than he’d expected, and it took him a moment to place Jonathan’s voice.

“Jonathan, sweetie, is Will home? Do you know where the other kids are?”

A brief shuffle came from the other end of the phone, and then Jonathan said, “Yeah, Will’s here, and his friends too.”

“Is El there?” Jim cut in, knowing she was supposed to be in the cabin, but she’d never listened to his rules anyway and he would really rather she not be alone right now, where he didn’t know if she was okay or not.

“Yeah, she’s here,” Jonathan answered, and Jim breathed a short sigh of relief. “Listen, Mom, there’s some stuff we have to tell you. About… about that thing that was in Will.”

Joyce closed her eyes briefly, but then proved she was still made of sterner stuff than anyone else in this town. “We know the gate’s open again,” she said, and Jim heard Jonathan’s intake of breath. “We were calling to tell you, actually.”

“Then you know about the Mind Flayers.” Was that _Flayers,_ as in plural?

Jim stepped closer to the phone. “There’s more than one?”

“Uh, yeah, but it’s kinda… maybe one of the kids should explain. Will? Could you come here a minute?” Jonathan’s voice got distant, and nothing else came through the line for a beat, which was just long enough for Jim to start worrying again.

“Mom? Chief Hopper?” Will’s voice broke the silence, and some of the tension visibly left Joyce’s shoulders.

“Oh honey I’m so glad to hear you’re okay. You are okay, right?”

Will’s voice was a little shaky, but considering the thing that had basically possessed him last year had come back out of the Upside Down, Jim figured it was warranted. “Yeah Mom, we’re okay.”

“What’s this about what Jonathan said, that there’s more than one of these Mind things?” Jim asked.

“Oh!” Will said, “Yeah, well, there’s one in this girl from the high school, Heather? I think… I think that’s the same one. But the one in Max’s brother is… different.”

Jim tensed. “Different how?” he asked, trying to push aside the vague protective feelings towards the girl who’d become his daughter’s closest friend, and the vague sense of dread that the bad stuff always, always had to happen to people they knew, to _kids_.

“Well it’s,” Will paused, sounding uncertain how to continue, “not really evil? I don’t know, but it was _talking_ to Billy, and we were talking to him, and last year that never really happened, and he didn’t seem like he’d hurt us, so-”

“Slow down, Will,” Joyce soothed her usually taciturn son. Jim couldn’t believe what he was hearing. A _nice_ possessing monster? He’d believe it when he saw it. He knew these kids had been through a lot, but he also knew that sometimes it was easier to believe something didn’t want to hurt you, when it was really just biding its time until it could. If the kids got to close to this thing, if El thought she could trust it, they might find that lesson out for themselves.

Over his dead body.

“So this other one is in Billy. He’s not with you now, right?”

“No,” Will said, “he’s with Steve and Dustin.”

“And where exactly are they now?”

~~

Some distant, tiny part of Steve, buried deep inside him right now, was panicking at the way the Russians were looming over him and Robin, but he really couldn’t hear it past the part of him that just couldn’t stop _laughing,_ even when it made his bruised ribs ache and left him wheezing for breath.

“Who do you work for?” their interrogator asked again.

Steve giggled like a schoolgirl. “Scoops.” Behind him Robin burst into laughter again.

Something resembling a smile found its way onto the Russian’s face, but he didn’t really look like he got the joke, and that was a shame because it was a _really_ good joke. Billy would have gotten it if he was here. Billy liked his jokes. They always made him give that little half-grin.

Steve’s attention was redirected by something latching onto his fingernail and tugging, and he yelped, struggling ineffectually to pull his hand back.

“The code!” Robin yelled, and the pressure on his nail receded, “that stupid code you broadcast. The silver cat?” She’d cracked that code like a total badass, Steve thought as she kept talking. He smiled a little thinking about it, how he and Dustin had been hopeless but Robin had translated and decoded in a day, and god that was cool. She was cool, cooler than he’d ever been when ‘King’ of Hawkins High.

“And who else knows about this code?” the interrogator asked, and when Steve didn’t say anything quick enough he got another punch to the gut for his trouble. He wheezed out a cough, and said, “Billy knows! I… I miss Billy. What happened to Billy? Oh, wait, he… he escaped. He’s gonna get us help, right Robin?”

“Steve,” she said in a mildly concerned tone, but it quickly bled away to more stifled laughter. “You guys are so fucked. He’s like, crazy strong. He’s gonna kick your asses. He’s got a parasite.”

“Is that so.” The man motioned for something behind him, where Steve couldn’t quite see, and one of the scientists brought forward a glass canister filled with something black and gooey. “I would not put much stock in your friend’s… parasite.”

Steve wriggled a little uncomfortably, though the bonds didn’t give him much room to move. “S’that?” he asked. “Not more weird drugs, c’mon, I still feel all funny from the last ones,” he whined. Maybe if he kicked up the puppy dog eyes they’d leave him and Robin alone instead.

The Russian only smirked. “Not quite,” he said, like he was telling a joke, but Steve didn’t find it that funny and he should, he was still hopped up on that laughing gas stuff. “We recovered this from your friend. Quite the force when bonded to a host it seems, but rather unintimidating when contained on its own, don’t you think?”

Steve blinked owlishly at the black goo. “ _That’s_ Mind Fucker? Whoa. Trippy. Where ya been, buddy!”

Twisting in her chair, Robin craned her neck in an attempt to see for herself. “I know you said he had something inside of him-” she broke off with a snort at her own wording, but kept going, “-but it’s kinda bitchin to see up close. Wait, where’s… where’s Billy then?”

This time is was the scientist who’d brought the Mind Fucker in that spoke. “We would have liked to use your friend as an opportunity to study the creatures that come out of the gate, but your friend was a bit… aggressive. Luckily for us, we have two test subjects who may be feeling a bit more amenable.” He eyed Steve’s bruises. “And if it proves to be a bit much for you in your current condition, well, that is no big loss either.”

Steve couldn’t think of anybody that would volunteer for _that_. He wasn’t sure where these Russians were getting these test subjects from, but they were crazy. The guy with the canister stepped forwards until he was right in Steve’s space, and abruptly Steve gulped and thought _oh_. “H-hang on, wait, you don’t wanna put that thing in me, really, I’m a bad test subject, always been shitty at science, ask Nancy she’ll tell you, never was any good at Bio, wait – wait, don’t open that!”

The lid released, Robin shouted “Steve!” from behind him, and something nasty landed on his face.

Steve’s head swam for a minute like a really shitty movie projector, and was this his life flashing before his eyes? Was he dying? Man, he really hadn’t wanted to die down here. He hoped Dustin would be okay without him. Maybe Billy could take over driving him to the arcade, the kid couldn’t bike there in the rain-

**_”Steve,”_** growled a _presence_ in the back of his mind and Steve yelped. Jesus, that was _scary_. How had Billy not jumped half a foot in the air every time the thing spoke? Billy was so brave… **_”Steve,"_** he repeated more firmly, and Steve tried to focus.

“That you, MF? Long time no see, man, what happened?”

Mind Fucker growled, but he didn’t seem angry at _Steve_ exactly, so he tried not to flinch. **_”Tried to evade capture. Didn’t work.”_** Yeah, that was an understatement. **_”I was, perhaps, wrong in running – I like you Steve, and so does Billy. I, for one,”_** he said, and Steve tried desperately to pay attention past the weird thrumming feeling at his words, **_“believe I have spent long enough running.”_**

Steve felt his arms give a tentative push against the ropes, testing them. Where before they’d felt as unbreakable as steel bars, they now felt hardly sturdier than strands of floss. Oh, those Russians had really fucked up with their attempted test. “All yours, man,” Steve said, resigning himself to the autopilot that was letting the Mind Fucker dictate his movements, because drugged him was really not in the right frame of mind to stage a prison escape. Mind Fucker, on the other hand, felt very strongly about prison escapes and his ability to execute them.

All they needed was a distraction – provided amazingly conveniently by the sudden blaring of alarms. The head interrogator left to check on them, and as he did the Mind Fucker pushed outwards with Steve’s arms and tore through the ropes like tissue paper. The remaining guards scrambled, attempting to reach some button on the wall, but they were slammed to the ground before they could, and Steve very carefully tuned out a bit because those drugs he’d been injected with and the vague motion sickness he was getting did not mix well.

In a matter of mere minutes, the Russians were laid out on the ground, and Steve had broken Robin’s bonds as well. “Time to go,” he said, tossing her a smile, and they moved to the door just as it burst open on its own and Steve narrowly missed taking the cattle prod Erica was brandishing to the chest. “Jesus!” he squawked, pin wheeling his arms a little because he was still kinda dizzy.

“Steve?” Dustin asked, looking around at the Russians sprawled out in various states of unconsciousness-or-death, Steve really didn’t want to know which. “How the hell did you do _all this_?”

Steve beamed. “Mind Fucker’s my buddy!” he declared, hearing an answering rumble of agreement from inside his head.

“The- the goop shit,” Robin attempted to clarify, but had to pause to stifle another laugh at Steve’s outburst, “they put it in Steve. Billy’s Mind thing. What a crazy day.”

“What the hell is up with you two?” Dustin pressed, and then with a healthy dose of mother hen concern, “And why does Steve look like he went three rounds with a truck and lost all three? _Again_?”

Dustin squinted at the two of them, who tried _really_ hard not to laugh again because his face just looked so silly. “Russian drugs!” Robin said, eyes wide and too-bright and yeah, that got them going again.

Steve deflated a little when he noticed Billy wasn’t with Dustin and Erica. That was a shame. He’d liked the way Billy had looked at him after he’d taken out that Russian guard in the com room. Now he’d taken out like five! If Billy had been there he would have said something about planting his feet and done that stupid tongue between his teeth thing and made Steve’s eyes crinkle at the corners like a giant goof. He’d really liked that. “Where’s Billy?”

“He went looking for the Mind Fucker,” Dustin said, ignoring Steve’s disapproving glare at his language. That’s what Billy called it, but Billy was an adult and Dustin was like six and he shouldn’t say stuff like that. “He was going to check the room he’d seen the scientists bring him into.”

“Which means he’s probably halfway across the base right now trying to find him,” Erica added, breaking Steve’s previous train of thought.

**_”I know where he is. Let’s go.”_**

And that worked for Steve, because he didn’t wanna leave without Billy. Plus he and Mind Fucker were cool and all, but he didn’t really want the guy in his head like, forever. “He said he knows where he is,” he relayed to Robin and the kids, waving them off. “We’re gonna go get him!”

“Steve, wait!” Dustin protested, but Steve was already halfway down the hallway.

~~

Billy ran a hand through his hair, considering how completely out of his depth he was right now. He had no Mind Fucker, and resultantly no superpowers, and he was stories underground in a Russian base with no clue where Mind Fucker might have escaped, or gotten moved, or otherwise ended up. And, he reminded himself with a downward twist of his lips, the guards must have noticed they were missing by now, which meant that troop of patrolling footsteps he heard was probably for him.

He pressed himself to the wall behind the door, hoping they wouldn’t come in here to look for him, even while knowing it would have been one of the first places he would have checked. Especially if the Mind Fucker really had escaped on his own and they didn’t know he was missing. But what else could he do? He couldn’t fight his way through after all, not in his current state.

A commotion outside the door interrupted the march of footsteps, replacing them with shouting and slamming and a general sense of chaos. Billy listened for a beat, then shifted the door open a crack, peering outside just in time to watch Steve Harrington punch into a guy from one side and come out the other.

He blinked, completely thrown. Billy had done that once before, right before they’d been captured, but that had only been with the help of… Oh no, you had to be kidding him.

As the last guard crumpled to the floor, Steve spun towards his hiding place and fixed him with a beatific smile that made warmth creep into his chest. And then Billy noticed the bruising all along the left side of Steve’s face, and the warmth turned to the hot pulse of rage.

“What happened to your face, Harrington?” Billy took his chin in a careful hand, tipping it to the right so he could see the extent of the damage. He hissed a breath in between his teeth, because it looked _bad,_ bad like Steve had looked when Billy was looming over him in the Byers’ living room.

“Oh, Russians,” Steve said with a near-flippant shrug. “S’okay, I think I had worse from Jonathan.” A laugh that sounded suspiciously like a giggle left Steve’s lips. “Oh, and they drugged us. Like, a lot. So if I think about your muscles when you held open that door out loud instead of in my head like usual that’s probably why. Wait…” That’s it. Billy’s brain had officially short-circuited, because there was no way he’d just heard Steve say what he thought he did.

“S-so Mind Fucker’s in there with you, right?” Billy asked, clutching desperately at the topic change.

“Oh yeah!” Steve’s face brightened instantly. “He said to tell you he fucked up. Like, royally. Controlling people s’not good. And he’s not gonna be a pussy anymore.” Steve frowned half-heartedly. “ _Language_.”

Billy sighed, knowing it wasn’t much of a promise, but also kind of wanting to believe it. He hadn’t meant to, but somewhere along the line he’d actually started to _like_ having the Mind Fucker around, even though he was kind of an asshole. But Billy was kind of an asshole too, so they worked well together, all things considered.

“Fine, apology accepted or whatever,” Billy relented, “we’re cool.”

Steve smiled again, then took a step forward and put a hand on Billy’s arm. Billy noted the strangeness of the position since he still had one hand pressed lightly against Steve’s jaw from looking at his face, and then he wasn’t thinking of much at all because Steve pressed closer and _kissed_ him. If he hadn’t feared missing this so badly Billy might have whited out from the shock of it all. Instead he only paused for the briefest of beats before he was reciprocating, totally lost in what was objectively a _really good_ kiss from Steve Harrington, and then the familiar weight of the Mind Fucker settled in his head once again and the two of them separated.

“Oh no,” Steve breathed, pupils blown wide, and Billy braced himself for the shouting that would come next, the demands to stay the fuck away from him, telling _everyone_ that Billy Hargrove was a- “I just shoved my arm through that guy’s chest.” He wasn’t looking at Billy but instead at one of the bodies on the ground, which was great because Billy really needed a second to catch his breath here. “We, uh, we should go. Robin and the kids are waiting for us.” He grabbed Billy by the arm like it was nothing, like he hadn’t just utterly shattered Billy’s world less than a minute ago, and started to march down the hallway.

Billy followed along dumbly for a bit, but eventually extricated himself, falling back a few steps. He hissed under his breath, “you can’t just _do_ stuff like that, man!”

**_”Why not? He liked it.”_** Billy really hoped Steve didn’t look back at him, because he could feel his face burning.

“Listen, maybe you don’t have these hang-ups in your dimension, but guys can’t go around kissing _other guys_ in Hawkins. When that drug fades Steve’s gonna remember what just happened, and if he decides he _didn’t like it_ …”

Mind Fucker gave a little chuckle. **_”You forget, I was in his head.”_** And that was officially too much for Billy to deal with right now. Shaking himself and firmly deciding he would deal with that when their lives weren’t in imminent danger, he jogged a little to catch up to Steve, hoping they wouldn’t run into any more guards on their way.

**Notes for the Chapter:**

> Steve, while drugged: Hey Mind Fucker, you were in Billy, and now you’re in me… that’s kinda like an indirect kiss
> 
> MF: I’ll show _you_ indirect


	11. Integration

“Jesus Christ, _there_ you are!” Dustin stared exasperatedly at where Steve and Billy had appeared after turning a corridor, flapping his arms dramatically. Well, _Billy_ was turning the corner – Steve was being practically dragged behind him, leaning half his body weight into Billy’s side, stumbling along behind him.

Robin let out a near-caterwaul of “Steeeeeve!” when she saw them, and Billy winced, hoping no one else had been around to hear that. “And Billy too! Oh good, we can go now!”

“God, don’t tell me she’s like this too?” Billy groaned. He was having enough trouble trying to get Steve to cooperate. “Perfect. Alright, what’s our plan for getting out of this hellhole?”

Dustin fished the elevator keycard they’d pilfered from the com’s guy out of his pocket and gestured to one of those motorized carts the people unloading the boxes from the elevator had ridden on. After a brief debate over who should drive it – which lasted only until Dustin pointed out that somebody had to keep Steve and Robin from falling out the back of the thing, and yeah, that was probably a valid concern – Billy ended up squished in the back with the two of them while Dustin and Erica sat up front and sped down the long hallway.

Billy sat near the back so he really could grab one of them if it looked like they were about to topple out, leaving Robin and Steve slightly crowded but at least marginally safer. Steve groaned after the second time Robin nearly elbowed him in the face and spread out closer to Billy, which left him sprawled against Billy’s left side, practically fucking cuddling. Billy willed his face not to flush. In almost any other circumstance he’d be in heaven, but he firmly reminded himself that Steve was _drugged_ and this was no time for spooning.

Robin stared at the way Steve smushed his face into Billy’s shoulder and giggled. “You guys’r cute,” she said, punctuating the ‘cute’ by stretching out her finger and booping Billy’s nose. Billy stiffened instantly, prompting another whine from Steve and a little shuffle and then Steve _did_ almost fall out of the cart and Billy had to grab him by the arm and firmly tug him back into place.

Steve laid a hand over Billy’s arm where it was still fisted in Steve’s shirt. “Strong… see, knew I was gonna start talking about your muscles.” Billy was saved the particular embarrassment of responding to that when Dustin crashed into some barrels and the cart came to a halt in front of the elevator doors. Unfortunately he was not so lucky when it came to the look Robin was fixing him with, almost like she _knew_ somehow, which was downright creepy considering how just a minute ago she’d been so lost she’d booped Billy’s nose. 

Awkwardly he extricated himself from Steve’s hold, hopping out of the cart and corralling them into the elevator. “Do you know what those Russians gave them?” Billy asked Dustin and Erica once they were moving, ignoring Steve’s baleful stare as he reached out the back of his hand to Steve’s forehead and felt the heat that emanated. “He’s really hot.”

“ _You’re_ really hot,” Steve countered like it didn’t break Billy’s fucking brain despite his best efforts to brush it off as the stupid comeback it probably was.

“Dude, _gross,_ ” Dustin complained. “Something is seriously wrong with him.”

Billy snatched his hand back, vowing to keep his hands to himself for the rest of the ride up. Said vow became a bit more complicated to keep once they reached the surface, where they took about three steps before drawing the attention of even more guards. Shuffling Steve and Robin ahead of him through the door Dustin had indicated, he wondered at what point they were going to _stop_ being chased.

They headed down snaking corridors, Steve and Robin laughing madly as they fled, each one being pulled forward by one of the kids. “Where are we _going_?” Steve asked, recovering from a stumble that had nearly sent him backwards into Billy’s chest.

“We’ve gotta find somewhere to hide, to blend in – somewhere like… there!” Dustin pushed ahead, opening another door to what looked to be the inside of the movie theater. “We can wait them out here.”

As they headed for a theater Steve snaked out his hand to snatch a half-eaten bag of popcorn from the top of the garbage can. Billy wrinkled his nose. “Don’t eat-” he started to admonish, but Steve had already stuffed a handful of the popcorn in his mouth and blinked up at Billy with big doe-eyes, so Billy cut himself off with a tired sigh and a shake of his head. “That’s disgusting,” he said, ignoring Steve’s mock-wounded look.

They snuck inside the theater, heading for the front row where there were still a few open seats. Dustin pushed Steve and Robin down into two seats, instructing them to “ _Stay_ ” while he, Billy, and Erica took three seats on the opposite end of the aisle. “Keep an eye on them,” he hissed to Billy after hardly a minute, digging around in Erica’s backpack and retrieving his walkie talkie and hopping out of the seat.

_Easier said than done,_ Billy thought to himself, looking back at where Steve and Robin were splitting their trash popcorn and trying to stifle giggles that ended up just on the side of too loud for a movie theater. He tore his gaze away, fiddling with a loose string sticking up from one of his arm rests.

He was surprised at how much it _hurt_ to see them laughing together, more than it had ever hurt to see Steve traipsing after that Wheeler chick for the first few weeks after he’d gotten to town. Maybe it was because he knew Steve better now, had had the most fucked up day of his life so far with the guy and come out the other side okay if a little worse for wear, had even _kissed_ the guy for fuck’s sake, weird as the conditions had been. He’d been in way over his head when it came to Steve Harrington before, but it had been easier to think about him as this untouchable guy, someone who Billy might pine over but never someone he seriously considered having any interest in him back.

But Steve had said all that stuff about thinking about his muscles and calling him hot and Mind Fucker insisted Steve had _wanted_ to kiss him, and all of the sudden Steve was not just some distant fantasy but someone real, maybe even attainable, someone Billy was starting to get to know and wanted to know better.

But Steve, it seemed, was head over heels for Robin. And who could blame the guy? Robin was pretty badass. Billy had to admit, at least in the (now relative) privacy of his mind, that if he had to watch Steve be with someone else he was okay with it being Robin. She was quick-witted and made Steve laugh and gave him those goofy little smiles. If Steve ended up with Robin, and she kept him smiling like that, that would be… okay. Billy thought he might be okay with just becoming Steve’s friend. And if he could say anything had come out of tonight, he was pretty sure he could now call Steve Harrington a friend.

_**”They left.”** _

“What?” Billy whispered, jerking in his chair to turn towards Steve and Robin – or rather, their empty seats. “Aw, shit.” Erica noticed the problem at about the same time, and of course that was when Dustin finally returned as well.

“I told you to watch them!”

~~

Steve slumped next to the toilet, head in his hands. Everything had finally stopped spinning, and while he still felt pretty fucked up, he thought he might finally be feeling a little more lucid.

And that left him with some things to think about. Like how he’d told Billy he thought about his muscles. And how he’d _kissed_ him. And how Billy hadn’t instantly punched him in the face afterwards, and instead had this wide-eyed, open look on his face. And how maybe Steve had sorta, kinda wanted to keep kissing him because Billy Hargrove was, objectively, a pretty good kisser.

That was probably the only reason why though. There definitely wasn’t anything _weird_ going on between him and Billy, right? Because he totally liked girls. He’d liked _Nancy_. But there was also a foggy memory of that one time at a party that he’d laid in the backyard with Chris Hensley and smoked through his stash of weed and maybe sort of thought about how nice it was to lay next to Chris like that and how Chris’ eyelashes fluttered against his cheek and maybe how he’d wanted to lean over and kiss him a little bit.

Jesus, he needed to stop getting high if this was going to happen every time.

Robin’s soft call of, “Ask me something,” broke his thoughts, and admittedly he was a little grateful, if confused.

“Huh?”

“To see if that drug’s out of our system. Interrogate me,” she added in a terrible Russian accent, which made Steve chuckle.

“Okay,” Steve said, and tried to think of something easy. “Uhhh… when was the last time you peed your pants?”

“Today,” Robin answered, sounding dead serious.

“What?” 

“When the Russian doctor took out the bone saw. It was just a little bit though!”

Steve laughed, feeling the grin pull at the bruises on his face. “Yeah it’s definitely still in our system,” he muttered, pressing a hand gingerly to his left eye. Was he just cursed to get the shit beat out of him every couple months? He really hoped not.

“My turn,” Robin decided, her tone light, but the question she asked decidedly more serious. “Have you… ever been in love?”

Steve snorted, because that was an easy one. “Yup, Nancy Wheeler, first semester senior year.”

“She’s _such_ a priss,” Robin complained, and Steve frowned a little. Things had been complicated with Nancy, they were still complicated honestly, and it still hurt a little bit to see her with Jonathan now, even if they were basically the only people from high school he still talked to. Well, until tonight that was. But he’d never seen someone look so self-confident facing down an eight foot monster. Nancy was special, that was for damn sure. “Are you still in love with Nancy?”

That was a harder question to answer. Steve thought about protesting, pointing out that she’d gotten her one question and it was his turn now, but figured that would sound more incriminating than any answer he could give. He was friendly with Nancy, even warm towards her, but did he still love her? “No,” he decided as he spoke. “Not really.”

“Why not?”

Now _that_ was a loaded question. His thoughts drifted again to Billy of all people, and he tipped his head back into the wall. He really hadn’t thought this much about Hargrove since he’d beat the shit out of him. But the Billy he’d seen tonight, and the Billy who’d tried to eat him out of house and home in ice cream, and yeah, even the Billy who’d gotten those guilty little looks on his face whenever he had seen Steve in the hallways between classes, felt worlds apart from the Billy that had only wanted to hit the next thing that moved. And Billy had apologized in the elevator, mumbled something so self-conscious and fumbling that it had to have been genuine. “I think… fuck. I think there might be someone else.”

Fuck. Was he in love with Billy Hargrove?

Wasn’t that just a recipe for disaster. Billy Hargrove, who’d charmed any girl he’d set his eyes on at school. Billy, who’d probably knock his lights out if he ever said any of this to him. Billy, who’d not only tolerated the Mind Fucker-encouraged kiss but _kissed him back_ and he really could not deal with these mixed signals right now.

“And who would that be?” For a second Steve’s heart leapt into his throat, because it almost sounded like she _knew_. But that would be crazy, right? There was no way she’d be thinking that.

He considered not elaborating. He’d really prefer to have whatever crisis he was going through somewhere other than the Starcourt Mall bathrooms, still half-high on Russian drugs. But he was tired of being, as Nancy had so eloquently put it, _bullshit_. And God, if you couldn’t tell the girl you’d almost gotten killed in a Russian base with that you might be harboring secret feelings for the guy you’d also almost died in a Russian base with, who _could_ you tell?

“It’s crazy,” Steve sighed, suddenly grateful for the stall that separated the two of them as he talked. “I don’t even know if I’m making sense here. But this… person that I like,” he said, ignoring how his throat tightened at the words, trying to shove down the possibility that he might be about to lose one of the only friends over the age of 14 that he had, “It’s somebody that I… barely even talked to before we graduated. Not about anything that mattered. I mean before these last couple days they were just this reminder of that one fucked up night. But they’re funny, and really nice when they want to be, and… well, they could stand up to just about anything.”

Steve blew out a breath, trying not to feel the weight of Robin’s silence. “It’s just so confusing. I mean, who wants to date the same guy who once broke a plate over their head, right?” Steve abruptly shut up. He hadn’t really meant to say that. But maybe it was better that he had. He drummed his fingers on his leg, feeling like he was coming apart at the seams as he waited for an answer. “Robin? Robin did you just OD in there?”

A startled laugh came from the other side of the wall. “No,” she said, and while she sounded a little surprised she didn’t sound _angry_ exactly. Abruptly Steve decided he didn’t like the barrier between him after all. He slid himself underneath the stall, sitting opposite of Robin and mirroring her position. “Floor’s disgusting,” she pointed out with a crinkle of her face, but Steve just shrugged.

“What do you think?” Steve asked, now that he could see her face.

Robin bit her lower lip, seeming to mull something over. Finally she said, “You remember what I was saying before, about Ms. Click’s class? About me being… jealous?”

Steve blinked a little, momentarily thrown at her non-answer. “Yeah,” he said slowly, sort of hoping this wasn’t the part where she was about to confess to him – because he really liked Robin, liked her more than he ever expected to, but that would be _really_ bad timing. Not to mention throw a bit of a wrench in Plan Robin-Send-Help-I-Might-Be-In-Love-With-A-Guy-Also-That’s-Okay-With-You-Right?

“It wasn’t because I had a crush on you,” she continued, and Steve gave a little internal sigh of relief, because that was too much to put on his plate right now. “It’s because… she wouldn’t stop staring at you. Tammy Thompson.”

Steve’s eyes widened, because oh. _Oh_. 

“I wanted her to look at _me_. But she couldn’t pull her eyes away from you. And I couldn’t understand, because you were a douchebag, and you didn’t even like her.”

Yeah, he remembered Tammy – kind of, in that way where when he’d been King Steve he’d known just enough about girls not quite on his popularity level that he could have them trailing behind him anyway. He really had been a douchebag; one more thing he and Billy had in common. If he wasn’t currently realizing some very startling things about himself, Steve might have said something dumb, like ‘Tammy Thompson’s a girl.’ As it was, he met Robin’s eyes and smiled a little, touched she’d met his confession with her own. And happy he wasn’t in this alone at least. “I mean, Tammy Thompson she’s cute and all, but she’s a total dud. Didn’t she want to be a singer, go to like Nashville and shit?”

“She has dreams!” Robin protested.

“She can’t even hold a tune!” Steve countered, and broke out into his worst possible rendition of Bonnie Tyler’s greatest hits, which sent Robin into a laughing fit. Steve watched her wipe a stray tear from the corner of her eye and was so, so happy to have met her.

“You know he looks at you,” Robin said, getting herself back under control, “when you’re not looking. He likes you. He calls you _pretty boy_ for God’s sake. I think you should tell him.”

Steve tried to believe her, he really did, but the thought that Billy Hargrove could like _him_? He just didn’t know. It didn’t feel real.

“Can’t believe you fell for _lady killer Hargrove_ and you’re giving me shit about Tammy!” she said, big grin back on her face. She squinted one of her eyes, mimed slicking back her hair, and contorted her face into something completely outrageous before delivering, “hey pretty boy,” in the worst attempt at deep and gravelly he’d ever heard.

“Oh my God, he does _not_ sound like that,” Steve cackled, hiding his face in his arm.

The door to the bathrooms swung open and Steve and Robin looked up, noted one very confused looking Billy Hargrove, looked back at each other, and immediately started laughing again. “Should I uh, give you two a minute or…?” Billy asked, raising a hand to the back of his neck.

“No no!” Steve protested, trying to calm down. “No, we’re good.” He pushed himself shakily to his feet, wobbling a little unsteadily before Billy reached out and grabbed him with a steadying grip on his shoulder. Steve caught Robin’s eye and dramatically waggled his eyebrows just out of Billy’s sight, and she nearly lost her own footing and slid back down the wall.

It took Dustin and Erica finding them and bitching about ‘wandering off’ like they were wayward toddlers to finally get them out of the bathroom.

**Notes for the Chapter:**

> The scene w/ Robin and Steve in the bathroom is legitimately my favorite Stranger Things scene ever and I KNEW I could not leave it out so here is a slightly longer than usual chapter to accommodate it (+ like double the gay). I'd die for Robin and I really hope we see a lot more of her in season 4.


	12. Synthesis

They exited the bathroom just in time to blend in with the wave of people exiting the theater. Greasy popcorn assaulted Billy’s senses from the middle of the crowd, to which Mind Fucker gave an intrigued grumble. **_”You have such interesting foods here. I would like to try this popped corn.”_**

“Yeah? Maybe some time when we’re not trying to hide from Russians. We’ll go on a movie date,” Billy whispered back, rolling his eyes.

**_”You could bring Steve on a movie date, I get popped corn, it’s a win-win.”_ **

Billy stifled a sigh. As much as he’d like that, he doubted Robin would be very amenable to the idea. His eyes unconsciously located Steve in the crowd, who was still a little wobbly where he walked next to Robin but was doing his best to adhere to Dustin’s insistence of not drawing any attention to themselves.

Yeah, nothing said inconspicuous like being beat to hell in a blood-flecked _Scoops Ahoy_ uniform.

At the same moment Steve glanced back in the crowd and their eyes met, and Billy tried to look away in time but it looked like he was too late because Robin gave Steve and little shove and then Steve was dropping back to walk alongside him. “You alright man?” Steve asked, big eyes full of concern. Billy fixedly reminded himself Steve might not be so concerned if he knew why Billy kept staring at him.

Actually, now that it seemed the drug had mostly worked its way out of their systems, shouldn’t Steve be… mad? He had to remember that kiss, and now that he was with Robin he was pretty sure whatever immunity would have been extended to him in Steve’s drugged haze would probably be gone now. But Steve still didn’t look angry; if anything, he looked a little anxious and uncertain, which was sort of strange to see on King Steve.

“M’fine,” Billy grunted. Maybe the kiss would just sit as this unspoken thing between them forever, and they’d never mention it again, and that would be _fine_ he reminded himself, it would be perfectly okay, despite what certain Upside Down monsters had to say about things.

“Listen, you and Robin. I’m uh. I’m happy for you,” Billy forced out, even though he probably sounded like he was anything but.

Steve’s eyes went a little wide and he looked flustered. “Oh no, Robin and I aren’t- she’s uh- well it’s a long story she should probably tell you herself but we’re _not_ dating. Really,” he added at Billy’s unconvinced look.

“Then what was all that in the bathroom? The two of you seemed like you were really getting along.” He knew some of his anxiety was bleeding into his tone now. He needed to shut up, before Steve saw right through him-

Confusion was rapidly replaced by realization on Steve’s face. “Oh my God, you big idiot. Robin was _right_.” Billy bristled even as he had no fucking clue what Steve was talking about. What had Robin said? She couldn’t know _that,_ could she? Had he been so obvious?

“Right about what? Whatever Robin thinks she knows-” Billy didn’t get a chance to finish that statement, because he nearly bumped into the rest of their group, who had stopped dead in their tracks and were staring at where the same Russian security guard that had chased them into the movie theater was standing by the doors.

“Abort,” Dustin said, spinning to face them, “ _Abort!_ ” Billy cursed under his breath. It was just one guy, and he knew he could have taken him out easily, but in the crowd of moviegoers? It was probably best to _not_ alert everyone in Hawkins to his apparent superpowers, or catch anyone in the crossfire. But they could wait out the crowd, he thought even as the guy looked up and they doubled back, scrambling for some kind of cover, and then more and more guards seemed to emerge at every turn and Billy figured he really should have dealt with that _one_ guy when he’d had the chance.

They slid down the middle of the escalator, scrambling over the counter of _Great Cookie_ and ducking down low as they could manage. 

“Do these guys ever give up?” Erica asked in a quiet whisper that still managed to retain her usual biting edge.

“And here I thought we were almost in the clear,” Dustin added. They both got quieting looks from Robin. Footsteps drew nearer.

Billy tried to level out his breathing, which sounded like harsh panting in the quiet of the lower floor of the mall. Something nudged against his hand and he jolted a little, then looked to see Steve’s hand just brushing the back of his own. He glanced up at Steve’s face, seeing the determined set of Steve’s jaw, and wordlessly gripped his hand in his own, giving it a quick squeeze. Harrington was planting his feet; maybe Billy should do the same.

“I’m gonna make a distraction,” he said. Mind Fucker hummed an affirmative, clearly ready to stop running as well, even while the rest of the group tried to protest. “When the coast is clear, _run_ ,” he insisted, punctuating it with another squeeze of Steve’s hand before he pulled himself free and started to stand.

He managed to get over the counter before the Russians spotted him and trained their guns on him. He edged slowly to his right, pulling their focus and any potential stray bullets away from _Great Cookie’s_ counter. “Now I hope none of you have those fucking cattle prods this time,” he said, “that shit fucking _hurt_.”

While it looked like none of them did, they still drew closer with their guns, and Billy figured the only reason he wasn’t dead yet was that they’d rather take Mind Fucker alive than risk killing them both. Billy just hoped he’d gotten far enough away that the others could try to sneak away, though he didn’t dare look and blow their cover. If the Russians changed their minds… well, he hoped Mind Fucker’s superpowers covered either really good dodging or miraculous bullet invincibility.

A loud crunch of metal pulled his focus behind the Russians, and his eyes widened at the fucking _car_ that was flipping end over end and hurtling for them. He ducked backwards as it slammed into his pursuers, holding up a hand to deflect bits of metal and plastic as the car soared in front of him and came to a shuddering halt where it had crashed into the wall.

He looked around him at the bodies the car had left behind, then towards where the car had come from, and finally _up,_ where he saw that girl, El, hand outstretched and blood dripping from her nose.

Yeah, that was pretty fucking cool. 

~~

“You flung that thing like a Hot Wheel!” Dustin shouted as he threw himself into a hug with El and Mike. El had a soft, pleased look on her face, even as she swiped at dried blood.

Billy pulled his attention away when Max shouted his name and ran up to him, and it was a little weird to see her looking so relieved to see him. “Are you okay? We got Dustin’s message, kind of – something about the mall and Russians?”

“M’fine, twerp,” he said, grinning and ruffling her hair a little. Wouldn’t do for the kid to think he’d gone soft or anything. “And uh, looks like your friend took care of said Russians,” he added, gesturing to the wreckage of the car.

“And the uh…” Max pulled a face, “that thing inside you…”

**_”Thing?!”_ **

Billy couldn’t help the upward twitch of his lips. “Mind Fucker and I are cool,” he reassured, and though she looked a little confused at the name she ultimately shrugged and accepted it.

“It’s the Mind-” Mike started to protest, but quailed at Billy’s scowl.

“Mind. Fucker. He likes it.”

“I’m sorry,” Robin cut in, “I don’t understand what happened to that car.”

“Oh, El has superpowers,” Steve said, “She threw it with her mind.” Robin gave an exhausted toss of her hands, but after spending the last few days in the company of Mind Fucker, she must have figured it wasn’t that much weirder that some fourteen year old was able to chuck a car with her head.

“Steve?” another female voice called, and jogging up behind the kids was Wheeler and the older Byers kid. “What happened to your face?” She fixed an accusatory look at Billy, who narrowed his eyes despite it not being such a bad guess, historically.

“Wasn’t me this time, princess.” Nancy’s nostrils flared, annoyed and unconvinced.

“He’s right, that was the Russians,” Steve cut in before Billy could make things worse. “They beat me up, drugged me and Robin, it was a whole thing,” he said in that same hand-wavey tone of voice he’d used for El’s powers, gesturing to Robin as he spoke in lieu of introducing her.

“ _Russians?_ Really?” Jonathan asked.

Max tugged at his sleeve to recapture his attention. “Billy, we have to talk,” she said, desperation leeching into her voice. “That other Mind Flayer, it really was inside Heather. And it knows about yours. We saw it, at the Byers’ house. It was…” she trailed off, looking lost for words.

Jesus, he’d almost forgotten about there being another one with everything that had been going on. He tried to remember what Mind Fucker had said about it in the beginning, that it was trying to build some kind of body, and thought maybe he understood Max’s shiver of unease. “Hey, it’s gonna take a lot more than some hopped up fuckin alien to beat me in a fist fight. Ask Steve.”

Max blinked at him, looking a little startled. “ _Steve?_ ” she asked, and right, he’d never called him Steve in front of her before, but it’d been a real fucked up couple of days – not that she had to know the details.

“El!” Mike yelped suddenly, and Billy spun to look just as the girl collapsed to the ground. Max gave him one last concerned look before moving to El’s side with the rest of the nerds, and Billy hung back a little, feeling out of place and not sure how to help, let alone what was wrong.

Even Steve had stepped forward to comfort El with those soft, sympathetic eyes of his, and Robin too, though her half-panicked ramblings about some kid getting hurt in a soccer game were somewhat less helpful. Billy looked on with a sort of morbid fascination as something seemed to slither and move within El’s leg.

He watched as Jonathan got up, only to return wielding one hell of a knife. Billy noticed Steve’s face go a little pale at the sight of it. Then El was yelling, and hovering her hand over the cut in her leg like she was about to flip another car or something, except this time she freed whatever the fuck had been in her leg and tossed it halfway across the mall floor. The thing, some kind of strange pulpy mess brought to life, wriggled across the floor a bit, until its progress was halted by the slam of a boot.

Said boot belonged to some guy in a really atrocious pink and green shirt. Probably not another Russian at least, though he did look kind of familiar. Wait. Was… that the Chief of Police? He snuck a glance back at Robin, who looked similarly confused about the Chief and the two other newcomers behind him. “Are we about to be arrested?” he asked lowly. The brunette woman and the guy with the beard in a wifebeater didn’t _look_ like any kind of cops he’d ever seen. Even if the woman had a set to her jaw like she was ready for anything.

“Dad?” El asked, still a little out of breath. Billy really hoped Chief Hopper and his crew knew about what was going on, because he really didn’t want to try to explain why part of an interdimensional monster had just come out of his daughter’s leg. He looked up at Hopper’s steely face and swallowed involuntarily; no, he _definitely_ didn’t want any part of that.

Unfortunately it seemed Hopper might have actually known a little _too_ much, because his gaze moved from the remains of what he’d crushed under his boot over to El, and then directly to Billy. “This is exactly what I knew would happen,” Hopper said, closing the gap between them in short strides and looming over Billy. “What the fuck was that thing, huh? That something from your Mind Flayer buddy?”

And Billy could have de-escalated, but he didn’t like the way Hopper was trying to posture, trying to get up in his face like Neil did, and his nerves were frayed from the whole night, and ultimately he was still kind of an asshole, so instead he snapped, “How the fuck should I know what that thing was?”

Hopper’s face twisted, but suddenly Steve was between the two of them. “Chief, wait, it wasn’t him. Billy wouldn’t do that.”

Hopper looked unconvinced. “I would think you’d know better than anyone just what Hargrove’s capable of.” A little of the fight went out of Billy at the reminder, and he looked away bitterly. Damn, was _everyone_ gonna keep bringing that up? “El, are you alright? Tell me the truth.”

El confirmed Steve’s assertion with a little shake of her head. “Not Billy. The other one.”

He still looked wary, but at least he wasn’t on a damn warpath for Billy anymore. “Fine. I don’t buy what you told me about a _good_ version of these things, and don’t think I’m not keeping a fucking eye on you Hargrove, but fine.” _Yeah, you and about half of everyone else here,_ Billy thought, not unaware of the glares Nancy and Jonathan still aimed his way. “If the other one did whatever the hell _that_ was to you, we’ve clearly got bigger fish to fry.”

Despite himself, Billy was a little warmed that the kids had vouched for him. Clearly they’d at least tried to warn Hopper that Mind Fucker wasn’t as bad as his predecessor, even if the warning had been pretty ineffectual. He was sure the kids didn’t really trust him or anything, but it was a little nice to know they didn’t think he was like, some kind of secret agent this whole time. He’d had enough of sneaking around to last him a lifetime after tonight.

~~

When tensions had finally smoothed over and appropriate introductions had been made, they attempted to compile their information. Billy was pressed to explain what had happened the night Mind Fucker had found him, and he did so while carefully _not_ including that first violating deep-dive into his psyche. Or the reason he had been out driving. Didn’t need either of the Wheelers on his case any more than they already were. Some of the suspicion seemed to leave Hopper’s eyes by the end of his little story at least, and Billy counted ‘no longer receiving quite as many death glares from a guy who could put you in jail’ as a win.

His piece said, Billy sat back and listened to the kids squabble to tell their side, interrupting each other and talking over one another when Mike decided Lucas was leaving out too many details or Max got frustrated with Mike getting hung up in the specifics. He rolled his eyes when the kids talked about their little sauna test, pretty sure that certain moments of heroism they bragged about had _not_ happened that way in his memory.

At only one point did Hopper interrupt, only to ask, “Wait, how exactly did you all get to the mall the first time?”

El, who’d been pretty quiet for most of their explanation, smiled, and Billy wondered if it would look too conspicuous if he started running now. “Billy drove us.”

“All of you? …In one car?” And oh, there were the death glares from Hopper again. He kissed that earlier win goodbye.

As the kids continued, Nancy and Jonathan occasionally cut in with clarifications once the story reached the hospital, and slowly explained what they’d learned about the Mind Flayer’s victims, especially their tendency to eat chemicals and melt into nasty blobs of flesh and bone.

**_”It is worse than I expected,”_** Mind Fucker said. **_”The other of my kind, the one they are calling Mind Flayer, was much faster in his plans than I anticipated. By now he may already have a well-formed body of his own.”_** Billy nodded his head in thought, but didn’t verbally reply, figuring that about the worst thing he could do for himself right now was interrupt Nancy Wheeler to talk to the voice in his head. He could do without that offended little glare of hers.

Hopper, Joyce, and Bauman recounted their own encounters with Russians and their knowledge of the lab under the mall, which Billy’s own group could expand on. He didn’t miss the way they bickered like an old married couple either.

Steve took over their group’s explanation, since he knew so much more about the Upside Down than the rest of them, except maybe Dustin, who seemed content to let Steve talk until he reached the part where they’d gotten drugged – then he and Erica kept butting in with how _annoying_ Steve and Robin had been, even as they were hiding grins at Steve’s mock-affronted responses. Billy noticed a few looks of horror and sympathy when Steve mentioned and then quickly glossed over their interrogation, ghosting a hand over the bruise on his face before returning it to his lap and moving on. Nancy especially looked like she was physically pained by the information, which was probably about the only thing Billy and Wheeler would ever agree on.

Aside from that, Billy took in Steve’s recounting of events with what had to look like a stupid little smile on his face, if anyone had cared to look. But they were so focused on what the machine opening the gate had looked like that he was pretty sure he was in the clear; that was, until he spotted Will of all people staring at him while trying not to look like he was staring at him. And yeah, the kid had seemed pretty invested in what Billy was saying when he talked about Mind Fucker, but he wasn’t talking about Mind Fucker anymore so why was the kid staring at him like that? Will, being caught out, studiously returned his focus to Steve, and Billy reminded himself that there was no way anyone knew shit from a stupid smile, least of all Will Byers who barely knew him.

Eventually everyone was relatively well caught up on anything that mattered – Steve had, obviously, chosen to leave things like the kiss out of his version of events – and deep into consideration about their next move. It seemed like a pretty sure bet that the Mind Flayer would be coming for them if it wasn’t already, and really, if Billy had to pick a place to die he didn’t want it to be this fucking mall.

“Giant flesh monster melting residents of Hawkins, Indiana down to build its body… not something I pictured getting myself into when I left the house for work two days ago.” Robin settled with a sigh next to him where he was reclined against the wall of the fountain. “Not something I would have thought was possible before tonight.”

Billy nodded in sympathy. “If I didn’t have another one inside me right now I might not believe it myself.” He sighed, glancing over to where Steve was standing behind Dustin and the rest of the kids, looking like the most long-suffering babysitter. “Hell, even then I didn’t want to believe it. I guess Steve helped with that. With trying to get past the initial reaction to ‘there’s a voice in my head and it’s dying for ice cream.’”

**_”A very cool, very helpful voice in your head. Who would greatly appreciate more ice cream sometime soon.”_** Billy chuckled.

“You might not see it this way, but you’re helping Steve too,” Robin said, tucking a stray piece of hair back behind her ear. “Gives him someone to talk about all this with who’s older than twelve.”

“He’s got you too for that, you know. Now that he’s dragged you into this.”

Robin’s smile was distant. “Maybe,” she conceded, and let the conversation lapse into silence for almost a minute before continuing at a lower volume. “Not the same way he’s got you though.”

Billy stiffened, because what was that supposed to mean except- 

“Relax. You’re pretty covert. I doubt anyone else has noticed.” She frowned, reconsidering. “Well, kinda. The ‘pretty boy’ stuff is a little over the top.”

Billy bristled, but kept his voice low. “You’ve got it all wrong-”

“But you know what they say,” she cut him off as if he hadn’t spoken at all, “takes one to know one.” 

And that was… unexpected. All the fight left him in a rush and he just blinked for a second, thoroughly caught off guard by the whole conversation. “Oh. That uh… yeah?”

“Wow. And I thought Steve’s response was lacking.”

Billy rolled his eyes. He briefly wondered exactly when Robin had found time or reason to tell Steve she was gay in the middle of being kidnapped by Russians. “You surprised me, s’all. That’s… that’s cool. I’m uh, well you already know I guess. But Steve…”

“Is a lot more interested than you seem to think,” she protested. From the back of his head the Mind Fucker gave the mental equivalent of a vindicated little fist pump. “If we somehow make it out of tonight alive, I think you two have a lot to talk about.”

Billy snorted, defaulting back to sarcastic to feel like he was back on solid ground instead of trying to parse what Robin was telling him. “If the Mind Flayer doesn’t kill me, I think Nancy Wheeler might.” Said Wheeler kept fixing him with narrowed eyes, and he could tell there was a conversation incoming that he very much would rather avoid.

“No kidding,” Robin laughed, knocking her shoulder into Billy’s as she got up. “Come on, it looks like the dingus needs rescuing.” She tipped her head toward where Steve was being fussed over by Joyce Byers, who had mothered him into letting her check out his injuries. It was kinda sweet actually. Billy rose and followed Robin over, decidedly _not_ thinking about their previous conversation.

Like Hopper had said, they had bigger fish to fry right now.

**Notes for the Chapter:**

> Billy: *repeatedly calls Steve pretty boy*  
> Robin: oh so you think he's pretty  
> Billy: *surprised pikachu face*
> 
> We’re in the endgame now. I’m expecting two, possibly three more chapters depending on how far I overshoot my outline lol. Plus an impulse to write a nice fluffy sequel fic 👀


	13. Mutation

“So it’s settled. Scoops Troop will head to the radio tower, you kids will go to Bauman’s, and we’ll head down into the base to close the gate.” 

Billy very resolutely did not snicker hearing ‘Scoops Troop’ come out of Hopper’s mouth. The guy had enough problems with him as it was. And he was happy to be lumped in with Steve, Robin, Dustin and Erica – probably about as happy as the others were to not attempt to fit him into one of the other groups, despite the help he might have offered in getting around the Russian lab at least. Joyce, to her credit, had said something to the effect of not wanting to put children in any more danger if she could help it, but Billy really doubted she cared that much about his wellbeing considering she barely knew him. Hey, if they wanted to risk their necks and reject his and Mind Fucker’s help, he certainly wasn’t going to complain about not having to spend even more time down there.

So Billy tried to nod and agree to his part in the plan, which should have been _fine,_ but nervous energy nipped at his twitching fingers. They had to close the gate, but if they did, what happened to the Mind Flayer inside him? Would it disappear too? Did he even _want_ that?

He’d be lying if he said he was entirely comfortable with the idea that Mind Fucker might stick around permanently, but he’d be just as big of a liar if he said he wanted the guy to be locked back in the other dimension. He hadn’t been lying to Max before. The two of them had started to get along, and he didn’t hate having him around so much, provided he actually respected Billy’s desire to be in control of his own body from now on.

Billy mentally kicked himself. He was getting _attached_ , wasn’t he? Just great.

And even better, as their loose congregation broke into smaller groups, none other than Nancy and Jonathan were approaching him. Just what he needed.

Nancy’s eyes were hard as she stalked up to him, carving a warpath, while Jonathan loomed behind, looking just as unfriendly but about half as aggressive. “Listen Hargrove,” she started, waving a pointed finger at him, “if you lay a hand on Steve I’ll-”

“I’m not gonna hurt Steve,” he insisted, ignoring Mind Fucker’s less than helpful addition of the other ways he could lay a hand on him.

Her mouth twisted. “You have before. Who’s to say you won’t do it again?”

“Really? Cause a little birdie told me about someone _else_ who beat the shit out of Harrington once,” Billy countered, looking behind her at Jonathan, whose flatly annoyed look quickly changed to one of guilt. Great, at least Billy wasn’t the only one who felt like shit about it.

“That was-” Jonathan started, but actually cut himself off before he could say ‘different.’ “You’re right. It wasn’t different at all, really. We just don’t want Steve getting hurt.”

_Newsflash Sherlock fucking Holmes, neither do I._ He didn’t say it out loud, though, not keen to reignite the fight. “Yeah, well. Don’t think there’s too much that’s gonna mess up that pretty face of his on top of a hill in the middle of nowhere, so we should be fine.”

Nancy looked at him then, actually met his eyes instead of just looking towards his general direction, and the anger ebbed a little from her eyes too, begrudgingly. She raised a hand to her opposite arm, clutching at the fabric of her sleeve. “Just make sure nothing does, okay? He seems like he trusts you, so don’t fuck it up, or the Mind Flayer in your head will be the least of your problems.”

Something about that hit a little close to home, not that Nancy seemed to pick up on the subtext. “Jesus, we’re not _dating,_ calm down with the overprotective dad angle.”

**_”You could be dating.”_ **

Billy privately reminded himself that no matter what Nancy thought, Mind Fucker could _never_ be the least of his problems.

Nancy was giving him a little affronted look, and right, Steve actually _had_ dated Nancy so she probably figured it had been just another dig. Well, let her think what she wanted then, so long as she wasn’t looking to actively fight him anymore. Their piece said, Nancy and Jonathan gave him one last nod and retreated, just in time to be replaced by Max.

Said step-sister in question stared up at him with a look Billy couldn’t identify. He raised an eyebrow. “Waiting for an invitation?”

“You are _such_ an asshole.”

“Oh real nice. If the Mind Flayer finds us I’ll be sure to remember those touching last words from you, Maxine,” he said, flashing her a teasing smirk.

“You’re not proving me wrong.” But she was smiling a little bit now, despite what must have been her best efforts to turn it into a scowl. “Just… try _not_ to get killed, alright? It’d be real inconvenient. You didn’t even put the Camaro in your will for me.”

“Not even if I was dead. I’ve seen the way you drive and the poor car doesn’t deserve that.” Billy glanced over to where the rest of Max’s friends were gathered. “Keep those shitbirds out of trouble, yeah? God knows they’ve all got a death wish, and Steve would be real torn up about it.”

“Yeah, I’m sure Steve would,” she agreed easily. She gave him another quick smirk before heading back to her friends.

Looked like it was time for them to go then. No backing out now.

The Camaro was still parked outside in the lot, but she wasn’t much of an off-road vehicle and he didn’t look forward to trying to scrape the mud off the wheels from the hill, so Billy didn’t mention her when Hopper tossed Steve the keys for something he called the “Toddfather.”

The Toddfather turned out to be a car Hopper had “borrowed” from some douchebag a state away, which Billy was more than happy to ruin with mud instead.

“Screw Todd, _Steve’s_ your daddy now!” Steve called as he slid into the driver’s seat with a shit-eating grin, and Billy ignored the little flip of his stomach as Dustin made gratuitous gagging sounds from the back seat.

Robin rolled her eyes, gave Billy a pointed look, then climbed into the back seat with the kids, leaving the passenger seat for Billy. Any attempts to make small talk with Steve that Robin had been intending, however, were drowned out by Dustin shouting instructions from the back, so Billy rolled his eyes and held his tongue.

A good ten minutes of shouted directions later, the Toddfather came to a halt a few yards from the top of the hill and didn’t seem like it was going to get much further. Steve gave a little disappointed dip of his head to his chest, bemoaning the defeat of the Toddfather before getting out with the rest of them following.

Robin gave them one look, then turned to Dustin and Erica. “Come on, let’s go.”

They started walking, but Dustin’s steps were slowed with suspicion. “Aren’t Steve and Billy coming- ow!” he cut off when Robin shoved him forward by the back of his head.

“Let’s _go,_ ” she repeated, “they’re probably in the lab by now waiting for us.” That left Steve and Billy to lean against the hood of the car, watching their slow trek up the hill.

**_”Say something,”_** Mind Fucker prompted. Billy grimaced, feeling the awkward tension build as the silence stretched on, but having no idea how to break it. Steve seemed similarly aware, tense where his arm brushed against Billy’s and staring resolutely upward towards the stars and, distantly, fireworks from the fair.

It was Steve who eventually broke the silence. “Hey, um. You wanna talk about that kiss?” In retrospect, the silence had been fine. Preferable, even. Steve’s eyes went a little wide like even he was surprised he’d said it, but he didn’t take it back, just waited for Billy’s response, whatever it may have been.

“Oh, uh, that? That wasn’t a kiss,” Billy insisted, feeling himself _blushing_ for God’s sake, what was he, twelve? “Mind Fucker just, uh-”

_**”Wanted you to kiss.”**_ _Not_ helpful.

“It was kinda nice,” Steve said, like it really was that easy. Billy shut his jaw with an audible snap, because _what_. 

**_”Told you so,”_** Mind Fucker teased, and Billy was _ignoring him_ because he really was the biggest pain in his ass. 

Steve finally turned a little to look at him, looking so open and uncertain and Billy was sure his own look of shock and mild panic was probably not the reaction Steve had in mind. But he couldn’t do much about it, because he was still stuck in processing. Steve floundered to recover at his silence. “Uh, but, if you didn’t like-”

“No!” Billy nearly slapped a hand over his mouth at Steve’s flinch. “Shit, I didn’t mean…” He looked away, over the side of the hill, taking a second to breathe. “I didn’t… hate it.”

Steve didn’t say anything for a second, but then gave an exaggerated gasp of offense. “Didn’t _hate_ it?” he echoed, and when Billy looked back at him he was pressing a hand to his chest, eyes lit teasingly. “I’ll have you know I am a _great_ kisser, and I am _wounded_ by your insinuation otherwise.”

“Oh?” Billy asked, playing along, even while feeling like he was stepping off a cliff, “if you’re so good, then prove it.”

A goofy little grin lit up Steve’s face. Billy carefully refrained from fist pumping like a much gayer John Bender (Max had _begged_ him to take her to the movies and no he absolutely would not admit to anyone out loud that he’d liked it, thank you very much).

“Hey!” Dustin was shouting down at them from the radio tower, halting the two of them in their tracks. “We’ve got a problem!”

“Raincheck?” Billy asked, sliding off the hood of the car and offering a hand to Steve, who grabbed it to pull himself up.

“Don’t make promises you can’t keep, Hargrove.”

“I never do.”

~~

The Mind Flayer had trapped the kids in the mall, and by the sound of that godawful roar he’d made his own body just like the kids had said. They listened to Dustin shout into the walkie talkie for a while, with no response, and watched the lights of Starcourt mall flicker in the distance. There had to be something they could do, but they were flying completely blind here.

Steve abruptly bolted upwards and took off down the hill. “Where are you going?!” Robin called after him, throwing her hands up.

“I’m gonna get those little shits out of there!” Steve yelled without turning back, making a beeline for the car. Of all the dumbass moves- Steve was going to get himself killed! Billy rolled his eyes and got up to follow, figuring that if Steve died like an idiot he’d never get to redeem that raincheck.

“Billy wait!” Dustin said, and Billy turned, ready to argue the point but Dustin just tossed him a walkie and told him to “keep in touch.” He nodded and kept moving, catching up with Steve just as he reached the car and swinging himself into the passenger seat.

Steve looked surprised, and then a little pleased. He turned the key in the ignition and the car jolted backwards, then in a tight circle, bumping down the hill until they reached the road and made straight for the mall.

“Hey Mind Fucker, what exactly are we going to find at the mall?”

**_”If we are lucky, we will be able to leave without drawing his attention. The Mind Flayer is much stronger than I am, especially if it has taken as many bodies as your friends say.”_ **

“So what are our chances?”

_**“Pretty much zero.”** _

Ah. That was comforting. “What’d he say?” Steve asked, looking like he could take a pretty good guess.

“We’re fucked.”

They arrived just in time to see Nancy Wheeler, standing in front of a car full of the kids, firing into the windshield of an oncoming car. Despite her best efforts, the car was only gaining speed, hurtling forward looking like it was angling to crash directly into them.

“Hold on to something,” Steve said, digging his fingers tight into the wheel. Billy had only a second to register what Steve was about to do and hang on for dear life as Steve put all his weight on the gas pedal. The Toddfather slammed headlong into the other car, knocking it off course and putting a pretty decent size dent in both the cars.

“Jesus Christ,” Billy breathed. “I’ve really gotta stop getting into car accidents this week.”

“You okay?” Steve asked, panting heavily himself, though it looked like he wasn’t much worse for wear from the crash. A little hard to tell though, considering the state he’d already been in.

“Yeah, I’m-” Billy’s eyes tracked movement along the roof of the mall and Steve turned to look as well. Crawling over the side was a horrifying mess of flesh, like the thing in El’s leg but about a thousand times bigger. The Mind Flayer’s limbs stretched out from the center like a spider as he pulled himself up and over the wall, and a mess of teeth was revealed as he gave the same gut-churning scream they’d heard over the walkie. “Holy shit. _That’s_ the Mind Flayer that got Heather?”

**_”Told you.”_ **

Speaking of Heather, had she been driving that car? Billy glanced inside, hardly recognizing the girl slumped at the wheel. Thick black veins stood out against sun-tanned skin, and black blood pooled in cuts from the crash. He’d seen those same veins on himself, but only really that first night, or in the lab when Mind Fucker wasn’t suppressing them. Was this what he would have looked like if Mind Fucker hadn’t defected? Or would he just be a pile of flesh inside that thing?

Mind Fucker's grumble sounded distinctly judgmental. **_"Shoddy work."_**

Someone laying on a car horn pulled his attention away, as did Nancy yelling for them to both get in the car. Billy and Steve crammed in the back, Billy taking a moment to lament not being able to reach the Camaro, which was tragically parked on the other side of the Mind Flayer. He really hoped she didn’t get stepped on.

Fortunately for his car and less fortunately for Billy himself, the Mind Flayer was following them, lumbering down the road and keeping pace with the car. He and Steve stared out the back window and silently willed Jonathan to drive faster. Their walkie crackled to life between them, but the voice on the end calling “Do you copy, Dustie-poo?” was _not_ one he recognized.

“I copy Suzie,” and that was Dustin’s voice this time, and who the hell-

“She’s real?!” Steve, Billy, and about half the kids said in unison. It sounded like Dustin was trying to get some number out of her. He listened with half an ear, up until the _singing_ started, and really, what the fuck was going on?

Billy lowered his voice, using the noise of Dustin’s shrieking to shield his voice from the kids overhearing. “Y’know Steve I’m fine with the kissing, but I don’t think this whole co-parenting thing is gonna work out, so you’re still in charge of the brats.”

Steve grinned. “What, you don’t think it’s romantic? It’s like we’re being _serenaded_.”

“Yeah, by a castrated cat.”

Eventually the singing died out and Suzie gave a number, which Billy hoped was at least useful to one of them, because _he_ sure as fuck didn’t need it. The car lapsed back into silence, only punctuated by the footsteps of the three story tall fucking monster still chasing them, until, all of a sudden, it wasn’t.

“It’s turning around.” Steve frowned. “Why’s it turning around?”

“You think it’s tired?” Lucas asked. For probably the first time since getting in the car Billy tore his eyes away from their pursuer and looked at the kids, and thought it was weird he and Steve had even fit in the car at all, since it had been such a struggle to cram them all into the Camaro and-

“Wait, aren’t there usually more of you little shits?” Billy asked, finding the back seat of the car noticeably emptier than expected now that he looked. El wasn’t there for one, and neither was the younger Wheeler, or- “ _Where’s Maxine?_ ”

**Notes for the Chapter:**

> Dustin: *sings Neverending Story*  
> Steve @ Billy: Aw babe, it’s our song
> 
> Also is it strange to anyone else that in canon they just. Leave Max, El, and Mike at the mall. Like I assume it was an attempt at drawing the Mind Flayer away I guess but Nancy that’s your _brother_
> 
> It’s looking like next chapter just might be the finale. And general reception to the idea of a sequel sounds pretty positive, so consider that to be in the works as well. After a short break, of course, because I need one lol ^^’


	14. Antidote

Billy was going to lose his shit. They’d _left_ Max at the fucking mall, not to mention El and Mike, where Heather had been enough of a threat to keep their whole group quarantined, and oh yeah, the giant fucking monster was on its way to them. Even though he’d seen Heather passed out behind the car wheel, he was far from positive she was out for good considering even Mind Fucker had been able to take a good number of hits. Leaving the three kids alone was stupid enough if it was only her, but knowing that monster was going to be there too?

He didn’t even want to _picture_ the ‘we left Max behind and she got eaten by a three story flesh monster, oops’ conversation he’d be having with Neil if she wasn’t okay.

Jonathan peeled back into the mall lot just in time to see the Mind Flayer disappear into the jagged gap it’d left in the roof. “Okay, what are we going to do about that thing?” Jonathan asked, spinning from the driver’s seat. “We’ve just got to slow it down until Mom and Hopper shut the gate, but I don’t know if we have anything that’ll hurt it, and it’s not like we have enough fire power to…” He trailed off, obviously thinking of something, but Lucas beat him to the punch; he held up a box filled to the brim with all kinds of fireworks.

“Anybody got a lighter?” Lucas asked, and Billy fished one out of his pocket, handing it over. They piled out of the car, each grabbing a handful, except for Billy who bit his lip and stood back a few steps.

 ** _”You’re about to have us do something very stupid, aren’t you.”_** Billy nodded. **_”I should have expected this.”_**

Steve noticed his hesitation and turned with a confused frown. “What are you waiting for?”

“Fireworks are fine, but it’ll see you coming a mile away. Unless you have a distraction.”

Steve stiffened. “Billy, no, that’s a terrible idea. Do _not_ -”

“Hey, your terrible idea was running off half-cocked and crashing the car. This is mine.”

Steve hesitated, but then his jaw set in determination. “Fine, but I’m coming with you. I can fight ugly too you know.”

“You are _not_ ,” Billy protested. “Stay here and throw fireworks and don’t get yourself killed, Harrington.” 

“Oh that’s bullshit!” Steve tried to protest again, but Billy knew they couldn’t afford to stand here and argue. 

“Relax, I’ll be fine,” Billy called as he started to back towards the mall entrance. And then, because he couldn’t help himself, he winked and added, “still gotta cash in that raincheck, Princess!”

Whatever he had expected to see inside the mall, this wasn’t it. Heather, looking even worse than before, was crouched over El, who she had pinned to the mall floor right in front of the monster. He didn’t see Max or Mike anywhere, and hoped they were hiding somewhere he and the Mind Flayer couldn’t see. He approached the scene carefully, trying to get just close enough to be noticed but far enough away that he wouldn’t get a tentacle through the chest before he could even provide a decent distraction.

Heather looked up at his approach with a smile that looked more like a grimace. “So nice of you to finally join us, after you ignored me for so long. Looks like you’re just in time for the grand finale.”

 ** _”Not here for you. Leave the girl alone.”_** Billy was startled to hear Mind Fucker’s voice coming out of _his_ mouth. But it didn’t feel like Mind Fucker had taken him over again, not entirely. It was more like they were _both_ saying the words.

“Oh, grown a spine, have you?” Heather mocked. She watched them, and Billy got the impression she was looking at _him,_ not just Mind Fucker now. “Do I have you to thank for that? …Billy Hargrove. What a shame. I’d hoped you wouldn’t get in the way. Not that you’re a threat.”

The Mind Flayer behind her swiveled its head – mouth – thing to face them for the first time, and its jaws parted to reveal rows and rows of slavering teeth. A limb slammed down just feet away, and Billy backed up, but didn’t run yet. He had to keep it in the middle of the mall, where the hell was-

Something sparked and exploded against the Mind Flayer’s head in a burst of light and heat, and the thing gave an awful screech, tossing its jaws blindly from side to side. More came from the top floor, raining down in a shower of fireworks that left the monster to mindlessly blunder around the mall, smacking against storefronts and demolishing benches. Heather seemed similarly incapacitated for the time being, letting out gasping breaths like she was being punched every time a firework landed, which meant he was in the clear to take El and get the fuck out of there.

He shot over to where El had begun to scramble backwards and offered her a hand up. “Come on kid, let’s get you out of here,” he said, hauling her to her feet and letting her lean against him when her injured leg wouldn’t take her weight. 

Something reached out and grabbed El’s leg, and she toppled, yelping and clinging to Billy’s arm as she was pulled backwards. Heather, who was kneeling on the floor, had her fingers dug into the wound. Billy grabbed her wrist and wrenched it free right as another firework collided with the Mind Flayer, loosening her grip. And then the fireworks… stopped.

Shit. They must have run out. Heather’s snarl curved into a sharp grin as the Mind Flayer recovered, pissed as ever. Billy stared up at it with wide eyes, unable to do much more than shove El behind him and stand his ground. “Hope you can take a punch, man,” he hissed to Mind Fucker, raising his arms as the Mind Flayer’s jaws parted and something with _teeth_ shot out from its center.

He caught the appendage, gritting his teeth as the force of the impact shoved him back a foot. He could feel Mind Fucker giving it his all, but they were losing ground, and that was only to its _tongue_. His arms shook with exertion.

 ** _”So much for facing things head on.”_** There was a grimace in the Mind Fucker’s voice, but he sounded resolved. Billy understood the sentiment.

Somewhere behind him, Max shrieked, “ _Billy!_ ” and he felt relief wash over him in a wave. He didn’t dare turn around, but if she could still yell that loud, then she was gonna be okay. He couldn’t pry his eyes away from the Mind Flayer. Two of its limbs lifted from the ground, poised to strike.

He really regretted not being able to cash in that raincheck with Steve.

A feral caterwaul sounded from his right, and something _slammed_ into the Mind Flayer’s tongue, making the thing shriek in pain and pull the tongue back into its maw. Billy stumbled forward a step with the momentum, and felt a steadying hand on his chest. He looked up and met the eyes of one Steve Harrington - stupid, idiotic, amazing Steve Harrington – who wielded a nail bat splattered with thick black blood. “Told you I could fight ugly.”

Billy rolled his eyes. “So not the time, Steve.” But he was smiling, breathless with happiness as he watched Steve take another swing at an arm that had gotten too close. They backed up together, Steve warding the Mind Flayer off and Billy blocking anything that tried to slip past him while the monster howled in fury and then, abruptly, in anger and panic.

Heather’s eyes were wide and she clutched at her head. Billy could feel a buzzing in his own skull, but he pushed through; he had to keep standing. Heather snarled at him. “You! Look what you’ve done! How… you’re a weak, cowardly fool!”

Mind Fucker’s voice joined Billy’s own again. **_”Someone taught me to plant my feet.”_**

“If the gate closes, you’ll go too,” Heather promised darkly. It felt true enough; Billy’s head felt like it was splitting apart, and he could sense Mind Fucker’s presence fading. “You host isn’t strong enough; this whole damn _body_ wasn’t strong enough for me. And when we’re both back there, I’ll make you regret this.”

Instead of deigning that with a response, Mind Fucker spoke inside Billy’s head once more, just to him. _**”Your world is more important – more worthy of protecting – than I once believed. Thank you for showing me that, Billy. I would have liked to have seen more of it with you.”**_

“Shit, don’t- ah!” He fisted a hand in his hair and crashed to his knees, lost in the spark of pain. Distantly he was aware of the Mind Flayer stumbling, shuddering, and falling in a heap. More closely he was aware of a hand on his shoulder and a voice calling his name.

**_”Goodbye, Billy.”_ **

A final wave of pain hit him, practically blinding him, and when he could breathe and open his eyes again he felt _empty_ in a way he hadn’t since getting Mind Fucker back from the Russians.

Steve was still holding his shoulder, and Max had joined them, crouched next to Billy and oh, when had he ended up laying on the floor? Over her shoulder he could see El leaning into Mike, and even further back he thought he could just make out Heather beginning to stir, though the world was spinning a little so he wasn’t quite sure about that one.

“Holy shit man,” Steve said. “Thought you were a goner for a second there.”

Billy’s grin came just a touch too slow, but came nonetheless. “Like I said. Takes more than some hopped up alien to make me kick the bucket.” 

Max just shook her head and, surprise of surprises, leaned forward and hugged him. “I’m glad you’re okay,” she whispered, before pulling back like she’d never hugged him in the first place. She got up to rejoin her friends with a final glance over her shoulder as she went.

Steve’s smile sobered a little. “So Mind Fucker, is he…?” He trailed off, looking uncertain.

Billy frowned, and tried to concentrate. He didn’t feel Mind Fucker’s presence like he had earlier, like he had gotten used to having another living being inside his head, but if he really focused, really chased what felt like scattered strings along the edges of his mind…

The voice that met him was weak, but there. **_”Don’t think I’ve forgotten about the popped corn you promised me. And ice cream. You owe me_ gallons _of ice cream.”_**

Billy’s laugh punched out of his lungs, full of pure relief. “Sure man, whatever you want.” That was answer enough for Steve, whose smile returned full force. “Don’t tell me you were worried?”

“Hey, he was in _my_ head too you know. Don’t act like you’re so special. And I _like_ him.”

 ** _”He is a good judge of character.”_** Which was ridiculous, because Steve had this crazy habit of looking at people who had punched him and giving them second chances they didn’t deserve, but that Billy couldn’t help but be grateful for.

~~

Their sorry looking group hobbled out of the mall on unsteady legs, half of them leaning on others for support. A whole host of ambulances was waiting for them, not to mention a good number of helicopters and some guys who looked like they just auditioned for the role of ‘corrupt government lab scientist’. Robin, Dustin, and Erica had made it back to the mall as well, and they sported matching smiles at seeing them all alive and relatively okay.

And if Robin’s smile was a touch wider at seeing the way Steve and Billy leaned into each other, no one else seemed to notice it.

Billy allowed the EMTs to poke and prod at his injuries, even when he knew he’d heal just fine; he didn’t imagine he should be letting anyone here know about Mind Fucker, and it seemed easier to avoid suspicion if he let them do as they pleased. Once they deemed him good enough they let him go, just in time to see Hopper, Joyce, and Bauman enter the parking lot from the elevator. Joyce tugged Hopper forward by the wrist, craning her head until she spotted Will and rushed over to him. Hopper noticed El at the same time, bundling her into a tight hug and resting his chin on her head.

Billy smiled. It was kind of sweet, not that he’d ever admit it. Someone bumped his elbow, and Billy looked over to see Max had come to stand next to him, and she didn’t look particularly happy about whatever she had to say. “Billy,” she started uncertainly, and Billy groaned inwardly in anticipation. “Neil’s been pissed since you left. Like, _really_ pissed. I… don’t know how he’ll react when you come home.”

There was a lot she wasn’t saying, which was just fine by Billy since he knew it all anyway. It figured, he could stand up to interdimensional monsters five times his size but Neil still sparked the urge to flee in him. Maybe he should take a page out of Mind Fucker’s book for once and actually follow the impulse. “Maybe I should move out.”

Max looked surprised, even a little pleased when he agreed going home might not be such a good idea, but she was soon frowning again. “I doubt the pool pays enough for an apartment.” If they took him back at all, that was, after both he and Heather’s disappearing stunts.

“Sounds like somebody needs a roommate,” Steve said as he wandered up behind him, and Billy jumped, wondering how much he’d overheard. But it didn’t seem like he’d caught much, if the light teasing smile on his face absent of any pity or anger was anything to go by. “What do you say, Hargrove? I’ve got a big McMansion and a guest room with your name on it.”

If Max hadn’t been standing right there, he might have said something corny like ‘at least buy me dinner first, Harrington.’ As it was, he just stared for a second, totally thrown. “Wouldn’t want to impose,” he tried, because he could hardly believe he’d heard right. People didn’t just let you move in with them on a whim, and they weren’t even technically _dating_ were they, it was more than he could ask.

Max gave him a hard look, because she had no idea what was making Billy gape like a fish. “Don’t be an idiot,” she chided, then seemed to remember _she_ wasn’t the one offering the favor and she couldn’t accept on Steve’s behalf. “It’d be fine, right Steve?”

Steve’s grin was sunny. “Course!” he said, meeting Billy’s eyes. “Not like my parents are ever around anyways.” He looked a little distant when he said that, but recovered quickly enough that Billy almost missed it. “Yo casa es su casa.”

“It’s _mi_ casa.”

“Exactly!” And Jesus, in the face of a patented Harrington smile like that, how was he supposed to say no?

~~

**Epilogue - Remission**

“Where the _fuck_ have you been?”

Neil looked like he was about to pop a vein, rounding on Billy the second he got inside. Billy was tired, and sweaty, and his heart felt like it as fucking soaring out of his chest or some other sappy shit like that, and he really did not have the energy to deal with Neil right now. “I told you. Out.”

This, unsurprisingly, did little to deter him. “If you think you can just walk back in here like nothing happened-”

“I’m moving out.” Billy punctuated the statement by walking to his room, digging around in the closet for a duffle bag. He could have Max bring him some stuff later, but he should really grab the essentials and a few changes of clothes now. He threw an assortment of shirts, jeans, and underwear into the bag, not bothering to fold anything, too focused on getting _out_.

Neil had followed him, and was standing in the doorway, blocking the exit. “And where do you think you’re going to go, exactly? You don’t have enough money with your dead-end job. And who’s gonna take in a fuck-up like you?”

 ** _”We could still kill him. Just a reminder.”_** Tempting as Mind Fucker made that seem, he was pretty sure that would put Max in an awkward spot. He would already make things weird enough for her with his exit – not that Neil really gave a shit whether he lived or died, so long as he was upholding whatever bullshit image he was expected to.

“I’m moving in with Steve. _Harrington._ ” And yeah, he knew Steve himself didn’t like to throw his family name around, but Steve wasn’t here and he figured he’d be forgiven if Steve could have seen the look on Neil’s face. They might have still been pretty new in town, but Neil knew all about the Harringtons just like everyone else.

“And what does a Harrington want with the likes of you?” A disgusted sneer overcame Neil’s temporary surprise. “Unless, he’s a fucking fa-”

Mind Fucker’s strength surged in his muscles as Billy moved forward, lightning-fast, shoving an arm underneath Neil’s throat and pinning him against the far wall. Neil’s eyes widened comically, and Billy might have laughed had he not been so pissed. “Don’t _fucking_ call him that,” he growled, leaning in just to watch Neil’s hands scrabble ineffectually at his arm. 

There was still a part of him that recoiled at the sight, that screamed ‘what are you doing he’s gonna _kill you,_ ’ but it was drowned out by the surety that Neil was never going to lay a finger on him again. He never had to set foot in this house again except on his own terms, and Neil had no power over him anymore. And while the Mind Fucker’s added strength and intimidation certainly had something to do with it, it was more than that, too – it was _Billy_ deciding he wasn’t going to be treated like this anymore.

“And if I _ever_ hear that you’re treating Max like you treated me?” Billy let some of the tension in his arm abate, letting Neil take a spluttering breath before forcing it out of him again. “ _Don’t_ let me hear that. It’d be in your best interest to leave her the fuck alone.”

Billy did let him go then, ignoring the Mind Fucker’s mild disappointment. He grabbed his duffle from where he’d dropped it at the foot of his bed – not his bed, not his room, not any longer – and hummed as he left the house for what would likely be the last time, letting the door shut with finality behind him.

He had a hot date with a certain pretty boy tonight, and he didn’t want to be late.

**Notes for the Chapter:**

> OKAY LADS IT’S TIME TO GET SENTIMENTAL
> 
> 3 weeks and 34,000 words later, we’re finally done! I’ve been absolutely BLOWN AWAY by the response to this fic. The comments, kudos, and hits on this fic are amazing, and if you’ve ever left a comment just know that I probably sat there staring at it and re-reading it and tearing up a lil bit before I could answer it. You’ve all been so amazingly kind, and have even provided some ideas/tweaks for the story itself. Thank you all for taking this wild ride with me!
> 
> You may have noticed that this work is now part of a series – yes, this means a sequel is in the works! I’m going to take a few days off from writing to refresh after the mad dash that was writing Toxicant, and to get a decent outline in place before I start writing its sequel. But it’s definitely on its way!


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